The Normal and Experimental Development of the Mammary Gland of the Rhesus Monkey, with Some Pathological Correlations [32(208)]

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CONTRIBUTIONS TO EMBRYOLOGY

VOLUME

Nos.

CARNEGIE

XXXII

207 TO 212

INSTITUTION OF WASHINGTON PUBLICATION WASHINGTON, D. C. 1948

575

This book issued

March 30, 1948

THE LORD BALTIMORE PRESS, BALTIMORE, MARYLAND A. HOEN AND COMPANY, BALTIMORE, MARYLAND

CONTENTS '

" 1

207. ALKALINE

\

PHOSPHATASE

208.

THE NORMAL

1—8

GLAND OF THE RHEsus MON

AND EXPERIMENTAL DEVELOPMENT OF THE MAMMARY

KEY, WITH SOME

(five plates) . . . . . .

George W. Corner

I

2‘

PAGEs

IN THE OVARIAN FOLLIcLE AND IN THE CORPUS LUTEUM

PATHOLOGIGAL

CORRELATIONs

(nineteen plates and three text figures) . . . . . . . . . I

9—65

Harold S peert 209. MIGRATION OF THE

\' 210. ‘

s

THE DEVELOPMENT cRINEs

AND THE

EMBRYOS FROM THE YOLK SAc TO THE PRIMITIVE

plates) . . . . . . . . . . . . . . . , I . . . . . . . . v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

IN MAN, WITH A CONsInERATION

OF THE GONAns

HIsTOGENEsIs OI= OVARIAN TUMORs

Iasap/l _ "2.11 DEVELOPMENTAL HORIZONS 1";

XVIII,

(six

OF THE ROLE OF FETAL ENDO

plates) I . I . . . . . . . . . . . . _ . . . . . . . . . . . .

DI

BEING THE THIRD ISSUE OF A SURVEY

‘

!PTION

..

81—131

'

Gillman

IN HUMAN EMBRYOS.

XV, XVI, XVII,

OF AGE GROUPs

OF THE CARNEGIE

(age group xv,

COLLECTION

three plates and seven text figures; age group xvi, three plates and eight text figures; age group xvii, three plates and eleven text figures; age group xviii, three plates and ten text figures) . I . I . . . . 133—203

L.

George

IN THE HUMAN EMBRYO (five plates, two colored,

H agcr

Padget

...

..

..

.

.

. . . . . .

...I

.

..............

. . .

. . . . _. . . . . . .

Dorcas

Streeter

.

OF THE CRANIAL ARTERIES

.

THE DEVELOPMENT

and thirteen text figures) . . . . . . v

. .

212.

.

; i»

l'

I

ANn

67-80

Emil Witschi

.

l

GERM CELLs OF HUMAN

GONAnAL FOLns (nine

...

..

205—261

CONTRIBUTIONS

TO EMBRYOLOGY,

NO.

208

THE NORMAL AND EXPERIMENTAL DEVELOPMENT OF THE MAMMARY GLAND OF THE RHESUS MONKEY, WITH SOME PATHOLOGICAL

HAROLD

Department of Embryology, Carnegie

CORRELATIONS

SPEERT

Institution of Washington, Baltimore

With nineteen plates and three text figures

CONTENTS PAGE ANATOMY

AND DEVELOPMENT

II

. . . . . . . . . . . . . . . . . . . . . . . __. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

II

....................................... ................................................

12

. .................................... .......... ......................................

12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

Embryo Newborn Adolescent

Adult

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Individual Variation

.......... .. ................. ....................................... .........

I3

..

15

THE MALE GLAND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

.................................... ..,.............................................

18

ROLE OF THE CORPUS LUTEUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . _ . _ . . . . . . . . . . .

20

Mammae

Supernumerary

CYCLIc CHANGES

NONEFFECT

OF HYSTERECTOMY

.......................................... ................................................

27

........ ........................... ...... ................................................

29

OF CAsTRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , .. ............................... .. .. ............................................

Atrophic Changes

Proliferative Changes EFFECTS

21 22

INVOLUTION EEEECTs

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

.................................. ....... ....... .........................................

PREGNANCY LAcTATION

. . . . . . . . . . . . . . . . . . . . ., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32 32

............................ ................................................

33

OF HORMONEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . _ . . . . . . . . . . . . . . .

34

Estrogens

.... .. ... .................... ......... ................................................

34

.................................... ..................................... ...........

39

Progestogens

Gonadotrophins Androgens

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

............................. ................................................

44

OF HORMONEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46

Desoxycorticosterone MODE OF ACTION

4o

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Action on the Gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46

Action on the Nipple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . .

50

............... ........................... ................................................

55

SUMMARY

Acknowledgments LITERATURE

CITED

............................... ............. ..................... ..............

57

................................... ..................................... ...........

57

THE NORMAL AND EXPERIMENTAL DEVELOPMENT

THE MAMMARY GLAND

OF

OF THE RHESUS MONKEY, WITH SOME PATHOLOGICAL

CORRELATIONS

ANATOMY AND DEVELOPMENT EMBRYO

In

adult life, different species show marked differ

ences with respect

and

to number, size, shape,

developmental

of

physiology

the

graphs of the latter clearly revealed a definitive mam

structure,

mary

glands. These differences extend back through early stages of development various

even

species

back toward

earlier

striking similarity mammae.

in

to

distinguish

the

As one

goes

fetal life.

during

embryonic

however,

stages,

from

developing

the mammary

limb bud (fig. 4, pl. 1). There was no gross evidence of a mammary line extending to the posterior limb bud.

of C

examination

Histologic

479, on the other

hand, showed a mammary line running

a

along either

in the organogenesis of the

side of the entire ventral surface of the embryo, from

studies have been published, all

the anterior to the posterior limb bud, but best de

appears

Numerous

essential

and serve

primordium

line in the thoracic region, just caudad to the anterior

mammary

agreement, based on observations in the

veloped

in the thoracic

cow,

through

this region the line was seen as a paired

rabbit, guinea pig, mouse, rat, dog, cat, horse,

region.

In

section

cross

thickening of the epidermis projecting from the body

opossum, kangaroo, and human.

wall, medial and dorsal to the limb buds (fig. 5,

pl.

sheep, swine, goat, mole, fox, squirrel, porcupine, bat,

The earliest primordium of the mammary apparatus consists of the milk streak, a zone of the integument

The adjacent epidermis was composed of two

layers

by

an enlargement

and elongation

TABLE

of

As the germi

the cells of the stratum germinativum.

1

characterized

1).

ELIBRYOS EXALHNED FOR A LIALIMARY LINE

MONKEY

native cells proliferate, this paired epithelial structure,

of the individual

normal

and

mammae of later life.

C.-R.L.

1916,

forms, Schmidt

C.-R.L.

9.75 mm.).

and Schmitt

(1897)

were able to demonstrate the

A

Embryological

Collection

of

1).

.

s

the rhesus monkey was thus

gestation age of 34 days

(C.-R.L. 11.3 mm.), running along the entire ventral surface of the embryo. In the 11.9-mm. embryo the

the

the type and time of

mm., 7.4 mm., 5.4 mm.) this structure could not be identified. Specimens were not available for

in serial

At

earlier stages of development

(C.-R.L.

8

line of the macaque

the embryos were studied 499 and C 665.

the gross.

study

sec

of mammogenesis

development.

Stereoscopic photo 11

C

at

(fig.

mass

the milk line was the

caudal part of the line had disappeared, at least in

development of the mammary (table 1). tions except

of its component

Covering

group of specimens in the Carnegie was therefore examined,

aim of determining

All

and an

darker appearance than the sur

The mammary line in clearly demonstrated

rhesus monkey. the

tissues,

flattened layer of periderm

(1898)

early development of the mammary apparatus of the

with

rounding

because

milk line only in' the

been recorded concerning

stratum germinativum

the line presented

closely packed cells.

pectoral region.

No observations have

34 35

The cells of the mammary line proliferate from the former. In stained sections

In the human, in contrast with the polymastic mam malian

31

outer layer of periderm.

length 9.5 mm.; Brouha,

9 mm.; Lustig,

8.0 11.3 11.9

pl.

1905,

..

of cells, an internal

demonstrated this structure in earlier human embryos 1898, crown-rump

26% 29

the human for

the first time in an embryo of 15 mm. crown-rump length (Kallius, 1897). Subsequent investigators have (Schmitt,

.. ..

.4

7.4

..

6,

The mammary line was observed in

..

a

supernumerary

.........

501

477 . . . . . . . . 499.' . . . . . . . . 479 . . . . . . . . . 665 . . . . . . . . .

a

the direct forerunners

Crown-rumplength (mm.) Conceptionage (days)

c

localized elevations which appear along this line are

Embryo

C C C C

which runs longitudinally along the ventral surface of the embryo from the anterior to the posterior limb bud, develops into the Milchleiste or milk line. The

beyond

the 35th

day of

MAMMARY GLAND OF THE RHESUS MONKEY

12

NEWBORN

The mammary glands of the human

at birth

are

usually larger than those encountered in infancy and

In microscopic

childhood.

early

epithelium

found

is

numerous

mitotic

be

to

section the

duct

containing

hyperplastic,

figures, and secretory

activity

is

often present in the alveolar cells (Keiffer, 1902). These manifestations of mammary activity form but a part of the

stimulation

general pattern resulting from intense

of the entire genital system

late pregnancy, including

during

edema

8 months

usually

noted in some

(Hoeland,

and authors

pregnancy,

for as long as

These

phenomena

are

stimulation

of

have referred

At

monkeys.

birth the mammae formed

structures, their

inconspicuous

mani

external

only

tically flush with the skin, and no mammary

hormonal

1927).

to the

attributed

children

7 newborn

or “anchoring”

of the labia

During the early neonatal period uterine bleed

been

have also a pair of inguinal

festation being a small areola. The nipple was prac

ing (menstruatio neonatorum) and mammary secre tion (witches' milk) are frequently observed, the latter having

(The lemurs nipples, which are used for the attachment of the young, but no mammary parenchyma is associated with them.) Our material has included the mammary glands of

glands, situated in the pectoral region.

of the fetus

or scrotum and enlargement of the uterus (Halban, 1904).

monkey normally .has but a single pair of mammary

them

to

as

tissue

was palpable. By careful dissection under the binocu lar microscope the gland was found lying in a

thin

adherent to the skin, and

plane of connective tissue

measured 2 mm. or less in diameter. The parenchyma consisted of but a few short, poorly branched duets,

with no semblance

lobular

Of

A typical

structure.

specimen is shown in figure 7, plate I. When viewed in cross section

the ducts were found to be composed

tion is very strong that the placenta is the source of the

epithelium, four to six cells thick. The cells and nuclei were large, and mitotic figures were Often seen. The lumina of the ducts were empty and there was no evidence of secretory activity in the

high estrogen titer of pregnancy.

cells

manifestations of a fetal response gens,

since

these

to maternal

hormones appear in equal concen

trations in maternal and fetal blood.

truly

is

pregnancy

might

be

referred

to

fetal than as maternal hormones. tion is probably incorrect.

In common

The presump

Since the placenta

however,

fetal organ,

a

estro

of hyperplastic

(fig. 8, pl. 1). The gland consisted entirely of no alveoli had formed as yet. The

the estrogens

of

ducts at birth;

more properly

as

stroma was of an undifferentiated

The latter designa ‘

with all other primates,

the

rhesus

the

extramedullary

type

hemopoiesis which

and la/clged has

scribed in the breast of the human newborn

been

de

(Gruber,

192I).

ADOLEscENT

From such the

complex

a simple,

undifferentiated

mammary

tree

duct system

of the adult,

with

constituent lobules of alveoli, gradually unfolds.

its

The

hyperplastic epithelium seen in the duct linings Of the newborn

involutes

the

during

neonatal period;

the

ducts of Older infants were lined with only one or two layers of cells.

With

the

general somatic growth

of

the same rate, so that there was never any significant difference in size between them. In contrast with the constant rate of growth Aberle

development

seemed

Of the

entirely

prepregnancy the mammary

growth

of the mammae.

adequate, however,

development, gland

is

increase

neither

for

This

has

during

its

in thickness of

striking

nor easily

measurable.

The right and left glands

increased

in area at about

glands at puberty.

for

The

mammae of 3 25oo-gm. females were found to average Increase in size occurred up to a

body weight

indicator

rate

4 sq. cm. in area.

in the area of the

glands. Measurements of area have served as the sole

birth,

of the kidneys from the highest growth

the ovaries and mammary

the animal, branching and extension of the mammary ducts occurred, causing an increase

found

(1934b)

of about 5000 gm., at which stage of gland area of 7 animals

the average

was 100 sq. cm. Folley, (1939), from

Guthkelch,

and Zuckerman

the measurements of 26 preparations

from nonpregnant rhesus monkeys weighing 2200 and 7100 gm., have

reduce the growth

even

of the

between

thought it possible

mammary

A 20.0000138W1'", A

simple

formula

weight

range 3400 to 6060 gm.,

gland

to

to

the

over the body representing the

MAMMARY GLAND OF THE RHESUS MONKEY area of the gland

W

and

the

of the

body weight

These latter authors have also denied the oc

animal.

ovaries show no signs of either existing

whose were

probably

too

upon

based

small

a

of

series

encountered lobules of

we have frequently

animals;

or

Their observations, however,

luteinization.

previous

alveoli in prepubertal monkeys the ovaries of which showed no trace

currence of alveoli in the mammary glands of monkeys

13

observed.

been

As will be described in this respect has

of ovulation.

in detail later, marked

variation

On the other hand,

in parous

even

monkeys complete lobular atrophy of the mammary glands may be anticipated in the absence of sustained ovarian stimulation.

ADULT has

normally

a

two to ten excretory ducts.

single nipple containing

In the adult the nipples

average

about 10 mm. in

and are located at about the level of the sixth

length

the nipple; each branches repeatedly, forming derived

ultimately lobules

(fig. 9,

the

2). Surrounding

connective-tissue

loose

a com

the lobules of alveoli are

plex duct tree from which

pl.

of the rhesus monkey

a

breast

is

The

which

symphysis averaging about 82 per cent of the anterior

plied with one or more arteries which break up into are also surrounded

between the two nipples of the same animal, depend

network of fine vessels.

ing upon the mechanical stimuli to which they have

degree

nipple Both

during lactation. surrounded by an areola of variable size.

subjected, is

especially

structures take on a deep to

response

the

intense

red coloration

in

stimulation

of

hormonal

pregnancy and the mechanical stimulation of suckling.

As in many other mammals such

as the

rabbit,

of vascularity of the gland may

from figure 10, plate

delicate

An excellent idea of the high 2,

been

Each

is

of capillaries going to the individual

The ducts

which

shows

be obtained

region of

a

system

sup

gross mount following intravascular injection in vivo

with India ink. In nonpregnant animals the limits of the mammary by

occur, however, both among individual

dense

alveoli.

a

animals and

by

Wide variations may

Each lobule

a

I924).

a

costochondral junction, their distance above the pubic

trunk height (Schultz,

course the blood vessels.

stroma through

can neither be seen nor determined

glands

ternal palpation.

ex

During the latter part of pregnancy,

mouse, and rat, but not as in the human, the mam

however, the glands gradually

mary gland proper lies in a flat sheet of connective

becoming visibly and palpably enlarged when lacta

beneath and in close apposition to the skin.

In

tion sets in. When lactation

is

tissue

increase in thickness, at its height the

milk

fully mature animals the gland may extend above and

filled mammae assume

laterally into the axilla and below to the costal margin. A variable number of ducts radiate from the base of

and may hang in large folds below the costal margins

does

the

ranges in its physiologic responses branched, naked

to hormonal stimuli from the sparsely

duct system of infancy to the dense lobules of secreting the various phases

wide attention, as

literature.

is

mary development and involution tracted

evidenced

of mam

naturally

have

at

an extensive

Studies on various mammals are, for the

most part, in good agreement, for sible to obtain mammary

well controlled terest

and lactation.

pregnancy

late

by

characterizing

The nature and tempo of

it

alveoli

has

been

pos

specimens from them under

conditions.

Despite

the

greater in

in the human breast and the numerous studies

pl.

which have been made upon still exists

concerning

velopmental changes. Divergent for example, concerning

however, uncertainty

details of many of its de

the

views are still held,

the existence

and nature of

cyclic changes in the human mammary gland in rela tion to menstruation There

are

several

(Speert, I941). reasons for the difficulties

countered in studies of the human mamma. of its large size and conical shape the

in its entirety, as

gland

mounts

Thick

is

than

development

VARIATION

it

mammary gland.

It

its normal

2).

it,

No organ undergoes more profound changes in the course of

II,

is

INDIVIDUAL

(fig.

greatly increased proportions

difficult to study

possible with whole

of the glands of many laboratory sections

of the

whole

sections

of

(Ingleby

and Holly, 1939).

selected

regions

en

Because

breast

must

animals.

or microscopic be

relied

upon

Study of the latter must

MAMMARY GLAND OF THE RHESUS MONKEY

14

be undertaken, however, with the

wide

variations

may

full realization that

encountered

be

in

different

the

menstrual

pregnancy, or the puerperium.

cycle,

Moreover, wide differences existed among the glands

An equally serious diffi

of both normal

and castrated

culty is inherent in the nature of most of the material

received similar

treatment

regions of the same breast. which

has

been

Many specimens, for

studied.

ex

ample, have been Obtained from patients at operation for mammary

others have been obtained at

disease;

autopsy following debilitating

Few speci The great

illnesses.

mens could be judged completely normal. est difficulty in the study

however, probably

of human mammary glands,

lies in the tremendous

range of

animals which had with various endocrine

preparations.

In

instances many specimens were available

several

which represented identical physiologic states, such as the same day of the menstrual cycle, the

in

puerperium,

mounts and sections

different

of

pregnancy,

When

animals.

or the

these glands were compared

apparent that the most marked

it was immediately

variation which may exist among normal individuals.

individual

This

of castration, advanced pregnancy, or prolonged estro

has vitiated, in many instances, conclusions based

upon the comparison of glands from different women.

As

of his autopsies, Engel (1941) called to the great variation in structure and

a result

attention

amount of glandular

present in the breasts

tissue

Yet too little recognition

days Of the puerperium.

been accorded this important

ability

in the female mammary in the human

a cycle

during

pregnancy

obtained from a different

stage.

on

based

women,

of various hormones upon questioned

and its development

have been Likewise,

The most

gland.

purport to demonstrate

breast

numerous

has

vari

factor of individual

widely quoted papers which

be

or in the first few

who died intrapartum

26 women

of

each

specimens

representing

the demonstrated the mammary

effects

gland may

when the control and test specimens

have been obtained from different individuals.

The present studies were

full

appreciation of the importance Of this factor of indi It was expected that numerous vidual variability. questions processes

relating

to

physiologic

and experimental

in the mammary gland could be answered

from the study and correlation

of the large amount

of material on hand. Since all stages of the menstrual pregnancy, and involution were represented, it was anticipated that the reflection of these processes upon the mammary gland could be studied by exami

cycle,

nation Of the appropriate specimens. The material consisted almost exclusively of glands which had been removed

at

autopsy, however,

instances were previous

and' in only

genic treatment could

a

few

biopsy specimens available

a specific

with reasonable

be anticipated

cant range of individual

mammary

variation

pattern

A signifi

assurance.

was encountered

under all other circumstances.

The large majority of

mammary

the

from mature females. Examination revealed a striking mammary

of

individual

variation.

glands of two preadolescent monkeys

of

3150 gm. and The ovaries of both animals

the same size, weighing

approximately 3220 gm.

num

13, plate 2, for example, show the

12 and

Figures

range

glands were

Of a smaller

younger animals also

ber of mammae Obtained from

respectively.

were juvenile, showing no trace of previous ovulation. The great difference in size and development of the mammary glands is apparent in the figures. striking

begun without

also

variations existed. Only after a long period

were the extremes which

Equally

were encountered

in a series of mammary glands obtained from 24 adult In (see section on the male gland).

male monkeys an earlier

study of mammary

rhesus monkey,

Aberle

development

(1934b)

also

in the

mentioned

the

individual variation in the amount of parenchymal tissue

found in a small series of prepubertal females.

The largest group of specimens representing the physiologic

same

state

in the female were those

ob

II

Eighteen such speci days after ovulation. mens were studied, most of which were obtained for biopsy at the time of laparotomy for the recovery of tained

the

fertilized

of ovulation

ovum.

In

each

instance the diagnosis

was made preoperatively

by Dr. Hart

man, by means of bimanual palpation, and was con

from the same animal. After the laborious preparation

firmed at operation.

of a large number of gross mounts as well as histologic it was disappointing to find that no clear sections,

Comparison of these specimens revealed all gra dations of development, from thin glands with small, distributed lobules of collapsed alveoli and sparsely

sequence

of changes could be demonstrated when the

specimens were arranged according

to

the

stage

of

much interlobular

stroma to thick glands composed

MAMMARY GLAND OF THE RHESUS MONKEY of hypertrophic

lobules of patent alveoli which almost

completely replaced the interlobular clearly show these

two

two animals is much greater than any change

these

which normally occurs in the gland during the course

stroma. Figures

14 and 15, plate 3, are mounts prepared from

specimens which

15

biopsy

of a menstrual cycle. This obstacle

has been circum

vented in the present studies by means of multiple

extremes.

Both were taken from healthy mature female monkeys

serial biopsies in the same animal, at various phases

under physiologic

of mammary development or before and after experi

conditions

which

were apparently

identical. The impossibility of demonstrating diflerent stages

of a physiologic

mens obtained

The

degree

from

by comparing

process

two

of individual

such animals

is

mental

evident.

mammary variation between

is the number

of mammary

characteristic of primates, several

upon

as many as 10 mam

obtained

from

a single

animal. MAMMAE

All

glands

instances of super

were performed

Biopsies

In this manner,

mary specimens have been

SU PERNUMERARY

Although two

procedures.

alternate breasts.

speci

nipples in primates, including

supernumerary

those in the present series and the ones reported in the

numerary nipples have been reported in various species

literature,

besides the human.

nipples. In the human the great majority of super

These are summarized

in table 2.

TABLE

have

been below

situated

normally

the

2

SUPERNUMERARY NIPPLEs REPORTED IN PRIMATES

Species

Author

...... ...... ...... Cebus eapucinus (2 cases) . . . . . . Cebus fatuellus . . . . . . . . . . . . . . . Cebus hypoleucus . . . . . . . . . . . . . Papio pormrius (3 cases) . . . . . .

schmidti . . Cercopitbecus patas . . . . . Callithrix . . . . . . . . . . . . . . Cercopithecus

Pithecus satyrus . . . . . . . . . . . Macacus sinecus . . . . . . . . . . . Macacus cynomolgus . . . . . . . Macacus nemestrinus . . . . . . Macaca mulatta . . . . . . . . . . . Macaca

mulatta . . . . . . Hylobates lar . . . . . . . . Symphalangus . . . . . . . Chimpanzee (2 cases) .

.. .. .. ..

...... ...... ...... ......

........ ........ ........ ........

Year

Sex

.. ..

Beddard Sutton

1901

Female

1889

Male

..

Schickele

1899

.. ................ ................ ................

Schickele

1899 1899

.......... .......... .......... ..........

.........

... ... ... ............. ................ ................ ................ ................

...... ...... ...... ...... ...... ......

Schickele Schickele

Coolidge

. . . . ..

Elder

Bilateral 1 bilateral

Left Left Left Right Left

Female Female

Male

1935 Personal communication Personal communication

Schultz and Coolidge

Left

Female .........

1899 1935 1927

Hartman Zuekerman

Bilateral

Female .........

1889

Zuckerman

......

......... ......... .........

1886

Sutton Schickele

Bilateral

Left . . . . . . . . . Left

1899 1935

Zuckerman Owen

Side

Left Right

Female Female Female

1936

Bilateral

Male Chimpanzee

(2 cases) . . . . . . . . . . . . . . . . . . . . . . . . .

1933

Coolidge

Personal communication

In

Bilateral Bilateral

Female Female

Right I

a review of the mammary

approximately

one thousand

glands and protocols of monkeys

which

have

been recorded in the Carnegie Embryological Labora tory, thirteen cases of hyperthelia were encountered,

in addition

to the case previously reported by Hart

man (1927). This gives an incidence for the rhesus monkey of 1.4 per cent, a figure in general agreement with the best estimates

of this condition in the human.

The number and arrangement of

the supernumerary

numerary mammae likewise occur below the normal breasts the

(98.7

reverse

cent of the breasts,

per cent, Kajava

et al.,

although

1921),

hold for the Iapanese (88 per supernumeraries are above the normal

seems

Iwai,

to

1907).

The

supernumerary

nipples

tabulated here have all conformed to a position along the

approximate

course of the embryonic

extending from axilla to groin. monest site

for

accessory

mammae

nipples have been described briefly in an earlier report

(axillary,

thoracic, abdominal,

(Speert, 1942a) and are presented in detail in table 3.

In

positions,

these

This

in

the

human

and vulvar). mammae clearly

inguinal,

supernumerary

milk line,

is also the com

MAMMARY GLAND OF THE RHESUS MONKEY

16

of embryonic rudi

represent an abnormal persistence ments.

Yet occasional

aberrant breasts and buttock, explanation

cases

have

on the face,

for which has

ear,

The supernumerary

All

16, plate 3.

to hormonal

in the present series

nipples

smaller than the

gradations in size were encountered,

presence

areola (no. 593) to a nipple equal in size to the normal ones (no. 708).

nence

the supernumerary

nipples were in

breasts the

following

gland has a nipple, lactation ensues tion.

from the normal ones, except in a few

In the human, for example, the is often discovered for the end of pregnancy, and if the

stimuli.

of axillary

first time toward

however, the specimens ranging from a mere accessory

distinguishable

mammae appear to be biologically

Supernumerary

similar to the normally situated ones in their response

typical example is shown in figure

Histologically,

had a common

is strong that they at least

sumption parentage.

found.

been

A

neck, arm, thigh,

no satisfactory embryologic

were, in most instances, distinctly normal ones.

impossible to state that they Were twins, but the pre

of

reported

been

Zuckerman

and deepening

parturi—

in the promi

observed an increase

in the color of the accessory

nipple in his male rhesus monkey following a series of injections with estrin.

When

nipple

the accessory

of monkey no. L1 in the present series was painted

TABLE

3

MONKEYS WITH SUPERNUMERARY NIPPLES (PRESENT SERIES)

Monkey

Sex

Side

L1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Male 621 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . Female 118 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Female 224 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Female ' 272 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Female 273 . . . . . . . . . . . . . . . . . . . . . 313 . . . . . . . . . . . . . . . . . . . . . 418 . . . . . . . . . . . . . . . . . . . . . 593 . . . . . . . . . . . . . . . . . . . . .

................... ................... ................... ...................

......... ......... .........

......... 690 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

instances where the surface epithelium

In six

thinner in the former. chyma was associated

seemed

cases mammary

with the accessory

to be paren

nipple.

This

consisted usually of only a few short ducts, entirely distinct from the normal gland (fig. 17, pl. 3). The hereditary nature and familial occurrence of supernumerary mammae has been recognized in sheep

associating incidence

this

condition

of twinning.

also

Monkeys

with an increased nos.

272 and

273

Absent

Bilateral

Female Female

Left Left Left Right Left Right

Female Female Female Female

distinguished.

In

the

absence

Absent Present

the

Painted with estrone

response

being

The large

ever,

already realized its maximal Examination

comparable accessory

to

nipple

revealed the presence

of the

possibilities

of the underlying

parenchymal

of extensive arborization

had probably

growth

for

gland, how—

ducts and many end buds, suggesting occurred

that

in re

to the locally applied estrogen. Such treatment

mary growth

been

found effective in causing mam

in prepubertal male monkeys

could not be

1940b).

The gland’s

of accurate data it is

affected

by its location.

that they

Accessory areola

Present

ment of normal nipples.

sponse

in all other respects

Present Absent Absent

of no. 708 failed to respond to the local applica tion of estrogenic hormone, perhaps because of its

has previously

similar

Twins (P)

that which we have observed following similar treat

in the present series arrived together in the laboratory bilateral supernumerary nipples, and they appeared so

Right: present fPresent U46“: absent Absent

occurred,

color

from an animal dealer in New York City.

Each had

Painted with estrone

daily with an alcoholic solution of estrone (0.05 mg. per cc.) for 44 days, a marked increase in size and

having

A

Righ t

Present

Female

growth.

by Speert, 1942a). considerable body of suggestive evidence has arisen (review

Absent

. Bilateral

(Elder,

and man

Right Left

Remarks

Right

(Castle, 1924), swine (Wentworth, 1916), chimpanzee 1936),

Gland

responsiveness

to estrogen

(Speert, is un

MAMMARY GLAND OF THE RHESUS MONKEY

17

THE MALE GLAND The male members of all mammalian mammary

The mammae

have

species

numerically

are

smaller than those

usually

although

which

glands,

equal to

of the female.

are thus a class character rather than

a sexual character, although in some animals (e.g., the

(cited by Kfilliker, 1880) has between I and 137 gm. among 80 male breasts which he weighed.

46 mm.,

and Gruber

observed variations

mouse) nipples may be lacking in the male. The structure of the male mammary gland in the

mammary variation in the adult male rhesus monkey,

human has been the subject of relatively little interest,

the glands

In an effort to determine the extent of normal

and there is little general agreement at present as to

of 24 fully mature animals were studied. In the monkey, as in the human, extreme variations in

what constitutes its normal anatomy.

size and development were noted.

studied

injected

of knob-shaped

(1852), contrariwise,

in the male breast, tributed

(1852)

although

they

lobular

and without

endings on the

At about the

small ducts but never any alveoli. time Luschka

Langer

macerated specimens and re

and

ported the presence

same

described alveoli were sparsely dis— Subse

arrangement.

quent reports have failed to clarify this point. KOlliker (1880), for example, found

the

breasts

of males be

tween the ages of 20 and 30 years to be relatively well developed in size, with extensive branching of the ducts, but neither lobulated Geschickter l

for Henle (cited by Kalliker, 1880) has found the adult male breast to range in diameter from 6.5 to

(1943)

normal male breast.

alveoli.

nor containing

not observed lobules in the

has

Andrews and Kampmeier

on the contrary, have stated

(1927),

that a complex

system

of ducts and alveoli exists in every male breast.

Under conditions of abnormal hormonal tion,

such as occur

tumors,

in

association

the male mammary

gland

with

largements which

are

comastia.

(1928)

Haenel

stimula testicular

may attain ex

of bilateral 20 years

designated clinically has

even

en

as gyne

reported a case

lactation in a male which

persisted for

in association with a hypophyseal

tumor.

Such cases are clearly within the realm of pathology. Yet it has not been easy to make a sharp differentiation between normal and abnormal mammary glands in the male solely on the basis of the extent of their de

velopment, for great variations occur in this respect.

In

1845 Sir Astley

Cooper wrote of the male gland:

“It varies extremely in its magnitude, in some persons being only the size of a large pea, in others an inch in diameter, and I have seen it two inches or rather more,

and then it reaches

even

beyond the margins

of the areola." Langer (1852) stated that he had never met with such numerous variations as in the extent of the duct development in the male breast. measurements

Guthkelch,

and

consists of a relatively which nipple.

Direct

are in agreement with such statements,

Zuckerman

(1939)

have

that the mammary gland of the male macaque does

uncomplicated

duct system

not extend far beyond the base of the

Most of their 5 animals were not fully mature, of alveoli which appeared in the

and the clumps breast

of one animal were regarded as a manifestation

of gynecomastia. We have found, on the other hand, in agreement with Gardner and Van Wagenen (1938), wide variations in the area of the normal male breast.

The diameters of the glands ranged from a minimum of 3 mm. to a maximum of 31 mm. Our material has revealed,

in addition, extreme variability in regard

to the number

of ducts, their caliber, the extent of

branching, and the presence

development and give rise to the breast

tensive

Folley, stated

of alveoli.

Of end buds and lobules ‘ ‘

Representative glands are shown in figures 18 to 27, plate 4. These pictures illustrate better than can any verbal description the range of variation in the male mamma.

It

is immediately

apparent that no single

pattern can be regarded as characteristic of the adult male monkey.

All

the tiniest gland,

gradations were observed between

with

bare

ducts which

unbranched

did not extend beyond the nipple base, and the largest gland, with

extensive arborization

definite lobules of alveoli.

of the ducts and

In another gland, smaller

in area, even larger lobules were present.

In the present study on

the

most of the

monkey,

male specimens observed were devoid of alveoli. only a few was there definite lobule formation. of the studies on the human male breast based

literature,as

in the

have been

upon relatively few specimens. It is suggested,

therefore, that the disagreement which the

In

Most

to the

male may well

sampling.

still exists

in

normal occurrence of alveoli be

the

result of inadequate

MAMMARY GLAND OF THE RHESUS MONKEY

18

CYCLIC CHANGES In all mammalian

species thus far studied, postnatal

gland participates, in

development of the mammary

its early stages at least, in the general somatic growth

and

process

occurs

of

independently

With the

onset

lishment

of recurrent

the

gonads.

of puberty and the subsequent estab

and differentiation

of and

associated

species.

Turner

sexual cycles,

further

growth

occur in a manner characteristic

with the

type of sexual cycle of each

has reviewed the literature on

(1939)

the subject and has considered the postpubertal mam mary gland changes related to and dependent upon four

types

of

cycle:

estrous

continuous

(1)

estrus

ance

of new end buds, regression occurring

during

diestrus and proestrus. Cyclic changes in the guinea pig’s mammary gland have been well studied by Hesselberg and Loch (1916) , Loeb and Hesselberg (1917a, I9I7b), and Turner and (1933b). The essential features consist in mitotic proliferation of the glandular epithelium dur Gomez

of the cycle (up to ovulation), with the formation of many duct buds but no true lobules of alveoli. Proliferation is absent during the

ing the first phase

luteal phase

of the cycle,

so that gradual

regression

of the gland occurs. This is not to be interpreted as

(2) short estrous cycles (rat, mouse); estrous long cycles (guinea pig, heifer, monkey, (3)

an insensitivity

of the gland to the secretions

of the

corpus luteum,

but is rather a manifestation

of the

human); (4)

long latent period required by the guinea pig before

(rabbit, ferret);

seasonal

breeding periods (sheep,

goat,

hedgehog, fox, squirrel).

In

the absence

of ovulation,

development occurs in

the latter being dependent

The animals remain

upon the stimulus of copulation. in continuous

estrus

until

mating occurs, the mam

mary glands consisting of extensively branched duct trees

with few end buds but no true lobules. After under the influence of the corpus luteum

ovulation,

the extensive lobular development of pseudopregnancy is attained.

A

of

similar sequence

events

occurs in the

ferret.

The

duration

cycles

in the

rat and mouse vary in

with the various phases

in this brief

Even

between 4 and 6 days.

period changes in the mammary

glands, associated

of the cycle, have

been

ob

Sutter (192I) described an increased branch ing and extension of the duct system of the rat during served.

estrus

and postestrus,

with gradual regression during

diestrus and proestrus.

These

cyclic

changes have

not been emphasized by the studies of several

subse

In the rabbit

evident.

becomes

also

it is at

of the corpus luteum

least five days before the effect

on the growth of the mammary gland is seen (Ham mond and Marshall, 1914). A somewhat similar situa tion prevails in the heifer. In this species too the gland to but lagging

undergoes changes corresponding hind those occurring

be

in the corpus luteum, the mam

mary epithelium enlarging during the corpus luteum's and

development

(Hammond,

, estrous

luteum

of the corpus

response to the secretions

mammary

the rabbit no mammary

shriveling

its

during

Intracanalicular

1927).

involution

secretion

also

occurs just before heat begins, with resorption during the luteal phase.

In the

breeders

seasonal

no development

undergo

the

mammary

glands

during

anestrum.

At

consist of only a few branching the

nipple.

Duct growth

and

estrus,

the

of the breeding season the glands usually

beginning

ducts at the base of

occurs with

formation

lobule

ensues

the onset of

following

ovulation. By analogy with the several species mentioned, one

character were noted by Astwood,

quent workers, but alterations of a somewhat different Geschickter, and

would expect to find cyclic changes

Rausch (1937). These investigators found a secretory phase, manifested by a dilatation of the ducts and

glands of the primates. That alterations do occur in in relation to menstruation breast the human is

distention

strongly

of the end buds, occurring

and continuing

at

postestrus

into diestrus, with subsequent collapse

of these structures at the following proestrus. Studies by Turner and Gomez (1933a), Cole (I934), and Wieser

(1934)

are in general agreement

in the mouse.

the mammary

cycle

a proliferation

of the duct epithelium

At

concerning

estrus there is

with

a resultant

extension and dilatation of the tubules and the appear

increase

suggested

by

the

in the mammary

subjective

fullness

and

in size which many women experience before

the onset

of each monthly

flow.

In

cases of masto

dynia, exacerbations typically occur before the menses.

The occurrence of cyclic human

breast

has

been

changes

in the size of the

demonstrated objectively

by

means of measurements of X-ray silhouettes (Reimann and Seabold, 1933) and by volumetric determinations

MAMMARY GLAND OF THE RHESUS MONKEY (Geschickter,

Occasionally

1943).

appears even in the breasts

a

milky secretion

of virgins at the time of

concerning

The

tion has been observed with periodic molimina and the

an earlier report

of bloody

fluid

from

without

nipple

the

1922 Rosenburg

published a paper purporting

establish a histologic cycle autopsy room.

the

gland.

mammary

of the problem was reviewed in detail in

status

and the difficulties

(Speert, 1941),

attendant upon attempts to study the mammary cycle

in the human

mammary

No alveoli were found in

speci

mens representing the early interval, the glands con sisting merely of ducts and supporting

Cor

tissue.

No direct study

to

gland. His study was based on material obtained from the

human

the

in the human were pointed out.

uterine bleeding (Pfister, 1901).

In

or extent of any of

existence

changes described in

their menses, and in rare instances vicarious menstrua discharge

subhuman

has

undertaken

been

to ascertain

and nature of a mammary

the existence

in the

cycle

Heape, in his early studies on

primates.

the menstrual cycle of the macaque (I897),

that the nipples became

observed

swollen and deeply congested

at the time of menstruation.

From

the study of control

relating the mammary histology with an examination

mammary

of the ovaries, Rosenburg described a progressive bud

menstrual cycle

ding of the ducts and rapid proliferation

mental studies, no evidence has been found for cyclic

elements with the

thelial

of the epi

of lobules

formation

alveoli, dating from the time of ovulation

tinuing throughout

the

corpus luteum

of

and con

phase

of the

of menstruation,

onset

of the mam

and involution

glands removed

In

of either the rhesus monkey

and Diddle,

(Allen, Gardner, hamadryas

Papio

various times in the

at

in the course of subsequent experi

changes in the breasts

cycle. Degenerative changes were observed with the '

the

l9

(Parkes

mammary glands of 8 mature female monkeys which were having normal menstrual cycles.

tures became more advanced during the postmenstrual

were obtained from alternate breasts

Soon the alveoli disappeared completely, and

during the interval

the breast

was composed again

The specimens at intervals of

about one or two weeks, so that 12 menstrual cycles were represented in the composite material.

of ducts of varying sizes but no lobules.

the

The claims of Rosenburg were sharply criticized by Dieckmann (1925). The latter author rearranged

In

each instance the diagnosis of ovulation

by

Dr. Hartman

cases and found

Rosenburg’s

it possible to correlate

the histologic appearance of the mammary gland with the age of the patient.

In

so doing he noted that the

specimens consisting chiefly of ducts had been obtained from

the youngest

patients and

that progressively

more lobular development was found as the ages of the

patients increased.

therefore, the

Denying,

ex

of an epithelial cycle in the gland, as pictured

istence

by Rosenburg, Dieckmann

went on to describe a cycle

consisting of a premenstrual

swelling

with subsequent shrinkage during

of the lobules

the postmenstrual

period. These changes were attributed to the forma fluid within the intra

tion and resorption of edema

A

appeared both in

large number of studies have and

confirmation

in denial

of the

observations

of

In addition, claims

Rosenburg

and of Dieckmann.

have

presented for cyclic cytologic changes in

been

the glandular degree general

cells and for cyclic alterations in the

of cellular infiltration agreement has

yet

cycles

tion.

were ovulatory,

6 nonovulatory

by means

Seven laparotomies

Six of

(table 4). was made

of rectoabdominal palpa were also

performed,

at

which time the diagnosis was checked by inspection of ovaries.

the

In two instances fertilized

recovered. The onset

of menstruation

inspection of the daily vaginal

ova were

was noted by

In monkey

lavages.

no. 620 hysterectomy was performed on day 22 of the cycle.

Since menstruation

subsequently arbitrarily Study

failed

naturally

in this animal,

ovarian

the

occur

to cycle

was

recorded as of 28 days’ duration. mounts

of gross

of the

mammary

clearly revealed cyclic changes which

glands

appeared in a

definite temporal relation to the bleeding cycle. changes to be'described observed in the

breasts

The

occurred, howeVer, only fol—

No significant

lowing ovulation.

lobular stroma (Liippchenoedem).

1931).

the present study 35 biopsies were made of the

mary gland with retrogression of the epithelial struc— period.

or the baboon,

1935)

and Zuckerman,

during

alterations

nonovulatory

were men

strual cycles. Most

striking

and consistent of the changes was

the enlargement of the lobules which occurred the

premenstruum.

During the

10 days

during

or so pre

within,the stroma. No

ceding the onset of menstruation, progressive swelling

however,

of the lobules was observed, continuing into the period

been

reached,

TABLE

pl.

MAMMARY GLAND OF THE RHESUS MONKEY 4

spongelike appearance (fig. 29, 5). Gradual sub sidence of the alveolar distention occurred during

MAMMARY BIOPSY SPECIMENS OBTAINED AT VARIOUS STAGESOF THE MENSTRUAL CYCLE Remarks

period and early interval, so that

postmenstrual

the

by

Day of cycle

the middle of the subsequent cycle the lobules had to what appeared in the mounts

completely regressed Laparotomy;ovulation 12; hysterotomy

day

8

but were present in none of the nonovulatory ones.

In

3

laparotomy day 13; laparotomy

after

22

able.

the

6

of lobular day 17; removal with corpus of ovary luteum day 21

Ovulation

4 11

Ovulatory

11 2

Nonovulatory

17 24

This

palpation).

with difficulty

alveoli,

of

the

17

further

regression

were

clearly

in the gross mounts, giving

of the

discernible

to “the lobules

a

of

the

decided in stroma.

in size of the lobules

having

(fig. 31). striking contrast presented figures 29 and 31, which represent approximately

the same

stage of two successive

cycles,

the first fol

non lowing upon an ovulatory cycle, the second ovulatory one. The lobules of the latter specimen had a

enlargement

illustrated). bimanual

of the next cycle, (fig. 30). On day gland revealed essentially the same

no increase

picture,

This lobular

which

to

alveoli could be made out now only

occurred by

individual

day

(not (diagnosed

in the visible amount of interlobular

biopsy

appeared to be due entirely to the dilatation even

By

The individual

30

flow.

was apparent

swelling

cycle was nonovulatory

crease Laparotomy

9

of the menstrual

were swollen

size and had taken on

lobules was clearly seen and there was

21 681 . . . . .

the lobules

cycle,

more clearly (fig. 29). Mammary biopsy was repeated on day 10 of this cycle, at which time the subsidence

25

Nonovulatory

succeeding

spongy appearance, the dilated alveoli standing out

3

21

alveoli were clearly distinguish

This

about twice their former

11

Ovulatory

(diagnosed

2

hysterectomy

18 25

Ovulatory

ovulation

In the cycle was of 33 days’ duration. of biopsy specimen obtained 11 days later, on day

day 11;

Ovulation

of

The lobules were already enlarging

and the individual

6

627.....

occurrence

ll 0 Nonovulatory

the

laparotomy).

1

Ovulatory

well depicted in figures 28 to 31, plate

by

10 17 1

620.....

nonovulatory.

A

.

shrunk to

a

Nonovulatory

was

(monkey no. 612). Figure 28 shows the appearance of the gland on day 24 of an ovulatory cycle, 11 days

Ovulation

2

which

The contrast

5

24

Ovulatory

of

the first

cycles,

between the changes in the former and their absence

in the latter

5

612.....

successive

ovulatory and the second

a

15 22

Preceding cycle ovulatory; ovulation day 13;

by

8

Nonovulatory

animals mammary biopsies were compared dur

ing two

is

15 22

607.....

state

4

Nonovulatory

collapsed (fig. 30, pl. 5). These changes occurred, in varying degree, in all the ovulatory cycles, as

a

13 24

Ovulatory

a

Cycle

is

20

fraction of their former size.

ROLE OF THE CORPUS LUTEUM section the occurrence of lobular

enlargement of the mammary gland during presence

of

was shown a

menstruum

be

associated

with

the

corpus luteum, for the cyclic changes

described were found which

to

the pre

ovulation

in only

had occurred.

those

cycles

This finding

during in

agreement been

with numerous

made in several

observations

other species,

that

have

all indicating

a

the preceding

is

In

causal relation between the corpus luteum and mam mary development. This relation has been best studied in

the

rabbit,

beginning

with

the

experiments

of

Ancel and Bouin in 1911. The mammary glands were

MAMMARY GLAND OF THE RHESUS MONKEY removed

from

rabbits

pseudopregnant

various

at

following sterile coitus and it was found

intervals

that the extent of glandular

could be

development

Ham

correlated with the age of the corpus luteum. mond and Marshall

confirmed

(1914)

these findings

if

21

the corpora lutea were removed from rabbits at the

5th day of pseudopregnancy, distinct involution of the glands could be observed 72 hours later. In agree' ment with this was the report of Asdell and Salisbury development occurred fol

that no mammary

(1933)

in the rabbit and described a similar relation in the

lowing ovariectomy in rabbits which had

ferret (1930); in this species also, no mammary growth

with vasectomized bucks.

occurs during estrus,

Multiple corpora lutea usually occur bilaterally following the induction of ovulation in the rabbit.

formation

however prolonged,

Marshall and Halnan Gomez

(1934)

have

during

system

Turner

and

(1917)

and

shown that~the mammary gland

of the dog attains complete growth alveolar

before the

of the corpus luteum.

of the lobulo and

pseudopregnancy,

this

Interpretations

the results of

upon

based

experiments in this species

been mated

ablation

are therefore complicated

the fact that both ovaries were either entirely

by

removed or grossly disturbed.

Hence one cannot with

been attributed to the influence of the corpus luteum. Similar pseudopregnancy development has

absolute certainty attribute the resultant effects to the

been demonstrated in the mammary

interest,

has

and

(Rowlands

Parkes,

Daryuru: the entire

of

ascribed to the corpus luteum Hartman mary

(1921,

hypertrophy

during

growth

independent

been

has

(O'Donoghue,

also

been 1911).

demonstrated mam in the

pseudopregnancy

The initial growth impetus

opossum. have

has

1923)

In the marsupial

1935).

process

gland of the fox

of

gland following removal of the ovary containing Repeated bimanual

palpations were performed

must

strual cycle,

since

The other ovary, which was left in Jim, contained follicles but no corpora lutea. Figure

the ovary containing

32, plate 6, shows the condition of the mammary gland

with greatly enlarged lobules and dis

at this time,

tended alveoli. Mammary

before the

mammary

response

to

after operation.

the influence of the corpus luteum is detectable. the

ovaries of mice which

induced by the injection of extracts

is

of sheep anterior

pituitary or of human pregnancy urine results in the development of secondary ducts and alveolar buds in the mammary

glands, but these mammary effects do animals

occur

in

castrated

According

to

Selye,

persistence

of the corpora lutea may be produced in

not

(Bradbury,

Collip, and Thomson

1932).

(1934),

virgin rats by distention of the uterus with paraffin, and

the

mammary

undergo a degree

glands

of

animals

so

treated

of development typical of pseudo

the corpus luteum

was removed.

follows

of

on

no. 646, and on the 5th day after the first ovulation of the current season, day 21 of the men monkey

of the corpus luteum,

This is in contrast with observations in the

The luteinization

the

current corpus luteum, the other ovary being intact.

rabbit and cow, in which species a short latent period ovulation

It was of

luteum.

corpus

the

therefore, to study the monkey’s mammary

at least

mammary growth was observed to begin before ovu lation.

specific absence

biopsy was repeated

5 days

In this short time definite shrinkage

of the lobules had occurred (fig. 33, pl. 6), although the

individual

alveoli were still clearly seen.

Seven

days later another biopsy of the gland revealed further

regression

of

the

lobules,

as

smaller size and by an increase stroma. The individual

manifested

their

by

in the interlobular

alveoli were, for the most part,

no lo'nger distinguishable

(fig. 34, pl. 6). These changes are similar to those observed in the

mammary gland during normal ovulatory cycles, ex cept phase

for the more abrupt onset of the retrogressive brought

about by the surgical removal of the

The view

is therefore

pregnancy.

corpus luteum.

A new approach toward the pfoblem was made by Knaus (1930), who studied the effects of with drawal of the corpus luteum influence. He found that

that the changes in the macaque mammary gland dur

strengthened

ing the menstrual cycle are directly attributable to the hormonal activity of the corpus luteum.

NONEFFECT OF HYSTERECTOMY Prolongation

of the life of the corpus luteum can

be effected

in laboratory rodents by several techniques,

including

injection

of

gonadotrophic

hormones

of

pituitary or chorionic origin, gens,

administration

of estro

suckling or other mechanical stimulation

nipples,

and chronic

distention

of the

of the uterus.

To

MAMMARY GLAND OF THE RHESUS MONKEY

22

Leo Loeb

goes the credit for first demonstrating

that

increased longevity accrued to the corpus luteum fol

lowing hysterectomy in

In this report

the guinea pig.

sex skin, and examination

of

the ovaries at laparotomy,

in 5 hysterectomized macaques which were observed for 121 to 2I7 days after operation; and histologic

of the ovaries revealed no increase in follicular

(1923) and also in a later report (1927), Loeb described the mitotic proliferation and lobular growth, even

atresia. In 2 additional monkeys, hysterectomy follow

milk formation, which occurred in the mammary glands of hysterectomized animals, and he

ing parturition had no demonstrable effect on the resumption of ovarian activity, as indicated by the

attributed this mammary development to the activity

vaginal desquamation

occasional

of the corpus luteum.

experiments by Asdell

Later

sections

(Van Wagenen and Catchpole,

1941).

Hammond (1933), Loeb and Smith (1936), Gillard (1937), and Chu and Lee (1942) extended these observations in part to the rabbit, for it was

monkey’s

shown

that

after the operation, which was performed on the 22d

in this

species

and

hysterectomy

during pseudopregnancy

resulted in a prolongation

Since

no

observations

of the life

day of the cycle,

194x). Mammary

however, no further mammary development occurred

of hysterectomy and 5,

in the rabbit beyond that normally

tively.

on

the

Distinct

after ovulation

11 days

(Speert,

biopsies were made at the time

II,

23, and 30 days

postopera

of the lobules was ob

enlargement

between the time of operation and the 5th post operative day, which was the 27th day of the cycle served

pseudopregnancy. Observations in other species have failed to demon an efiect of hysterectomy on either the corpora

strate

made

been

following hysterectomy,

we studied monkey no. 620 in some detail for 6 months

of the corpora lutea. In contrast with the guinea pig, attained during

have

mammary- gland

and the time of the expected

maximal

effect of the

lutea or the mammary glands. In the rat, for example,

corpus luteum on the mammary gland.

removal of the uterus during any stage of the estrous

of these biopsy specimens appeared in a preliminary

cycle failed

report on the cyclic changes in the mammary

lutea

to produce

of the corpora

persistence

Fraenkel,

(Hechter,

Lev, and Soskin,

1940),

and Hartman (1925) found no difference between hysterectomized animals and normal controls in the diestrous involution

of the mammary glands of the

1941).

the contrary, rather prompt shrinkage of the lobules occurred, for the following cycle

opossum. Hysterectomy probably has no specific effect on the human

garded as a manifestation

which

some gynecologists

ovary, although

results from

circulation

the operation

to the gonads

may produce pre

mature menopausal symptoms in some women. have no effect on the ovaries. served

ectomy. normal

Hartman

During this period ovarian

cycles,

she

continued

as indicated

desquamation,

and at autopsy the

“an

state

excellent

Diddle

(1932)

ob

an animal for one year following total hyster

of

by

found

no

vaginal

ovaries were in

preservation.”

(1936), likewise

the

to have

Burford and impairment

of

ovarian function as manifested by the vaginal lavage,

was nonovulatory.

mammary

the

of

the

lobules was re of a func

absence

tional corpus luteum.

Four and one-half months following hysterectomy, laparotomy

In the monkey also, removal of the uterus seems to

gland

The subsequent biopsy specimens revealed no further development of the gland. On (Speert,

This retrogression of

believe that the impaired

Photographs

and bilateral

was repeated

ovariectomy

was performed, together with biopsy of the mammary gland.

biopsy was repeated

Mammary

45 days

later.

In the interim moderate diffuse lobular atrophy had set in, as well as the hyperplastic nodules which been

described

in

previously

castrates

have

with intact

uteri (Speert, 194oe). These castration changes will be referred to in a later section. Hysterectomy, there fore, appeared to have no effect on the

monkey’s

mammary gland, either before or after castration.

PREGNANCY With the exception of hypertrophy of the uterus, the

follows

parturition

are

unequaled,

either

by

the

changes in the mammary glands are the most striking

changes in other glands of the body or by the altera

which

tions in the mammary

occur in mammals

as a result of pregnancy.

The rapidity of the mammary

development

this period and the abruptness with which

during lactation

period of similar functional

gland itself during any other

duration.

significance

Because of the obvious

of the gestational growth

of

MAMMARY GLAND OF THE RHESUS MONKEY

phase of its development.

Previous reports by others

3d

about the

This was interpreted

month.

as the

structural basis for the formation of colostrum, which usually observed clinically only after the

3d

concerned themselves with this

is

gland, a large proportion of the studies

the mammary

of this organ have

23

month.

have described the pregnancy changes in the mam

The present studies

mary glands of the rat, mouse, bat, rabbit, squirrel,

made of the pregnancy

changes in the mammary

A

large number of biopsy speci

mens were studied, corresponding

is

(Roberts,

1921).

Similarly

in the mouse,

hyperplasia of the mammary parenchyma

is

days

21

practically complete

complete

day (Turner and Gomez, In duct and alveolar develop the guinea pig, 1933a). ment confined to the interval between the 20th and the end of the

12th

is

at

35th days

of

the 63- to 67-day period of gestation (Loeb

and Hesselberg,

1917a;

Turner and Gomez,

1933b).

Likewise in the goat, proliferation

of

alveolar system occurs predominantly

during the first

(Turner and Gomez,

pregnancy

and in cattle mammary growth

1936),

about the 5th month, or midway

is

half of the ISO-day

the lobulo

complete at

to term

(Turner,

Observations on the human breast during pregnancy are not entirely

satisfactory, as was pointed out pre

Yet they have

viously.

served

general tendencies of growth differentiation

during

to

indicate the same

in early pregnancy and

the later stages that have been

demonstrated in other species.

Lewis and Geschickter

described the rapid proliferation

(1934)

of the glandu

of pregnancy, with of the cells and dilatation of the alveoli

'

postpartum.

Monkey no. 654. Biopsies on days 23, 95, 128, 157, and 161 (parturition) of pregnancy, and days 24, 54, and

postpartum.

Monkey no. 690. Biopsies on days 30, 57, and 106 (par 15, 49, and 92 turition) of pregnancy, and days postpartum.

Great

individual

month.

pregnancy

has

Rapid formation also

been

of ductules in

observed

by

early

3d

of

the

Dawson

(1935), who described the casting off of the superficial cells

of

these newly

formed two-layered structures at

was found

In

some

the

among the

months of gesta

lobules were well developed, the

alveoli were moderately dilated, and mitotic were present.

figures

In others, representing corresponding

of early pregnancy,

stages

the

glandular

structures

were still poorly developed and did not even equal, in many instances, the

glands

of

nonpregnant

Despite these

during

during

variations in

pregnancy

have emerged

of our composite material.

In an examination of and

animals

early stages, certain general tendencies of mam

from the background 38,

encountered in

the development

some

normal menstrual cycles.

pl.

found the maximal development of

variation

specimens obtained during the first

the

gross mounts

(figs. 35—

6), little change was apparent between the 1st

3d

(1937)

single

Monkey no. 601. Biopsies on days 33, 68, 97, and 144 (parturition) of pregnancy, and days 17, 51, and 95

mary development

the galactophores at the end of the 2d and beginning

as

on each of the following:

the

Grynfeltt

as many

from

complete series of observations was made

maturation occurring

obtained

specimens being

biopsy

animal.

lar elements in the first third

chiefly during the latter half of gestation.

of involution,

pregnancy to completion

tion.

1934)~

was possible to follow in

a

gradual one. In the rat, for example,

the 13th day, secretory changes appearing from this point to term,

proliferation

By this method

stages.

the same monkey the sequence of changes from early

4,

is,

for

by

the most part,

a

of development, although the transition

stages

nancy up to term (165 days). Observations were made means of serial biopsies at various animals

on

3,

of the cells and enlarge

(secretory modification

ment of the alveoli). In the smaller animals rather fixed lines, have been drawn separating these two

it

tion

previous section. In addition, 25 pairs of mammary glands were on hand, representing later stages of preg by

of differentia

the later stages of gestation, is chiefly one

mens was extremely wide, as has been described in

A

the second, characterizing

87

and hyperplasia);

trophy

The range

of structural variation encountered among these speci

a

The first, occurring during the first part of pregnancy, consists predominantly in growth (hyper scribed.

to very early preg

nancies of 11 to 12 days conception age.

5

two types of change have been de

species

9

In each

have been

3,

human.

gland of the monkey.

2

goat, cow, and

hedgehog, guinea pig, dog, Daryurus,

are the first which

months of pregnancy.

about the same size, although

The lobules were of they had become ap

preciably denser in appearance (figs. 35, 36). The ducts were also of approximately the same caliber and

MAMMARY GLAND OF THE RHESUS MONKEY

trophy

Great hyper

lobules occurred, so that in the gross

Of the

mounts

glands under

the

in thickness.

progressively

interlobular

less

mained visible. The alveoli became

stroma

re

enlarged to such

lobular

The

stroma.

the end of the

month was due, in the main,

to the rapid multiplication

An

increasing

attested

number

more

in size of the lobules

increase

3d

month

3d

a

During the

thickness.

went a decided increase

by

24

of the alveoli

of

mitotic

(fig. 40).

figures

rate of proliferation.

rapid

further

The

an extent by the 4th month that they could be dis tinguished at the periphery of the lobules, even at low

alveolar cells also appeared larger. Superimposed upon

magnification (fig. 37). The blood

secretory activity in the mammary gland at this stage of pregnancy. The nuclei were basally located, many

more prominent

vessels also became

as a result of their increased caliber.

Specimens obtained at subsequent stages of pregnancy

this proliferative

activity were clear-cut evidences

cells contained supranuclear

of

vacuoles, and in others

jutted from the cell margins into

revealed still further increase in thickness of the gland.

secretory processes

The lobules

the lumina of the alveoli. The majority of the alveoli

progressively

became

larger, chiefly be

The individual

cause of the dilatation of their alveoli.

were more

or less

distended

and contained

small

the lobules as term was approached, despite the virtual

amounts of colostrum (fig. 40). This secretion, which was also present in the ducts, presented an amorphous

replacement of the interlobular

appearance microscopically

pl.

7). The paucity month of pregnancy

the same specimens (figs. 39—42, of lobular growth during the 1st was confirmed.

Glands which were poorly developed

at the time of conception still showed no better lobular

month than was observed

a

development at the end of such glands after

1

in many nonpregnant animals. Histologic

of

sections

month’s gestation showed lobules

which were just beginning

These were

of

observed in the colostrum of other species.

commonly

Secretory activity was well established in most glands the beginning of the 4th month of pregnancy. Some variation was encountered in this respect, how

In monkey no.

ever.

690, for example, there was no

evidence of secretion in histologic sections of the mam mary gland at 106 days. Biopsies at subsequent stages of pregnancy term

revealed

secretory

activity.

continuation

up to

and accentuation

of

The lobules became progressively

composed of small numbers of alveoli and were rather

larger and the alveoli became

sparsely spaced in an undifferentiated connective-tissue stroma (fig. 39). The patent alveoli were formed

with colostrum

by

to take form.

and gave no evidence

desquamated epithelial cells or leukocytes, which are

a

stroma by the en

larging lobules (fig. 38). The histologic basis for the gross changes observed in the mounts was revealed in microscopic sections of

by

alveoli were clearly distinguishable at the periphery of

(figs. 41, 42). nuclei increased in size, but as term was approached

moderately large cuboidal cells which contained large,

and the products of secretion distended the alveoli,

round

their

Through the stroma

sional mitotic figures were seen. coursed numerous

Occa

blood vessels, which

supplied the

lobules with dilated capillaries filled with red blood

became thinned

numbers.

months’ gestation revealed

the

individual

what larger and there was

of cytoplasm in

cells appeared some relative increase

the

latter.

in

The alveoli and amount

Speci

slight increase in the size of the lobules.

a

relatively

months.

a

mens obtained after

2

creasing rate during the 2d and

in

gradually

a

occurred at

proliferation

3d

Alveolar

Mitoses

the

were

slightly more numerous but were still not conspicuous. impetus to glandular

lobular

period, with

a

mendous

3d

greatest

manifest during the

month

hypertrophy

growth

became

of pregnancy. occurred

resultant relative decrease

Tre

out

in many

places.

in evidence in moderate

of the lobules became increas

Vascularity

ingly prominent

During the

cells.

The

walls

Mitotic figures continued

with the approach of parturition.

last trimester of pregnancy many glands

of eosinophiles in The significance of this finding

contained an increased proportion the blood vessels. not clear.

is

little cytoplasm.

have been described in the

Eosinophiles

stroma and among the alveoli in the breasts

of the

human newborn, and they are known to occur in the adult breast

also.

is

and relatively

distended

The cells and their

It

nuclei

increasingly

present in the mammary

probable that these cells are glands of other animals as

well, for Ieffers (1940) has described them in the bat at the time of parturition.

Many authors who have described the human mam

during this

mary gland during pregnancy have commented upon

in the inter

the

presence

in every

breast

of small lobules which

MAMMARY GLAND OF THE RHESUS MONKEY have failed to undergo the complete development of their

have been

These

neighbors.

termed virginal

lobules, and their failure to respond to the hormonal stimulation Recalcitrant

of this

lobules

never

en

mammary gland

every

or near term, all lobules were found to

at

structure.

were

sort

In

countered in the monkey.

to in

attributed

of pregnancy has been

focal deficiencies in the glandular

herent

have under

gone complete and rather uniform development.

The mitotic proliferation of the alveolar cells which is responsible

for the rapid growth

1887

of the mammary

was described as early as

gland in early pregnancy

in the glands of dogs, rabbits,

cats,

rats,

and

guinea pigs (Bizzozero and Vassale, 1887). In these species mitotic growth is restricted largely to the first

In the rat, for example, mitoses In 3 rare after the 13th day (Roberts, 1921).

stance

which at the same time causes growth of the

mammary

representing

Grynfeltt

studied,

(1936)

and last months of preg

nancy, no mitotic figures were found.

Our material,

clever

By

the

of the ovaries and placenta, and the inhibition

of

lactation to the latter organ. This theory has survived to the present day.

The early experiments of Lane-Claypon and Star ling (1906), Aschner and Grigoriu (1911), and Biedl and KOnigstein (1911), based on the injection of fetal into rabbits and guinea pigs, suggested the

extracts

fetus as the source of the mammotrophic has indicated

however,

the probable incorrectness of their con was later directed to the ovaries,

Attention

to the corpus luteum, as the agent re

during pseudopreg pregnancy. Ancel demonstrated the identity of the

sponsible for mammary

growth

nancy and, by implication, and Bouin

stimuli.

of this work,

reinterpretation

Subsequent

in particular

6th,

lactation.

mammary development of pregnancy to the influence

are

the 4th,

inhibits

developed this theory further, attributing

(1905)

clusions.

specimens which

and

gland

analysis of well known clinical observations, Halban

half of pregnancy. human

25

(1911)

during

with

by contrast, revealed an increased incidence of mitotic

mammary

figures in the mammary gland of the monkey during

which occur during the first part of pregnancy in the

the second half of gestation. Figure 43, plate 7, shows

rabbit (phase de développement gravidique).

an example of the frequency Of mitoses at term. This

changes were attributed directly

biopsy specimen, obtained at 157 days’ pregnancy and 4 days before parturition, contained numerous mitotic

the corpora lutea, but were held to be of different

including three consecutive

five of which,

figures,

changes of pseudopregnancy

origin from the of pregnancy

those

These

to the influence

of

changes of the latter part

secretory

(phase glandulaire

gravidique),

which

mary gland during the later stages of pregnancy is the

with the so-called myometrial gland Ancel, and The extraovarian origin (Bouin 1912). of the stimulus for mammary development during the

result of continued

latter part of pregnancy

mitoses in the wall of an alveolus, are shown in the

The enlargement of the monkey’s mam

photograph.

as

well

mitotic p'roliferation

Various

of the cells

of the alveoli.

as dilatation

experiments

(1906), and Stricker

of

Ribbert

Basch

(1898),

(1929), the parabiosis

ments of Ernst (1927), the nerve resections

experi

of Pfister

(1901), and the injection of hormones, have established beyond question the endocrine basis of the mammary of pregnancy.

development widely

for

accepted

many

This concept years;

yet

has

been

the precise

in the rabbit was further

by the failure of attainment of the final phases

attested

experimental procedures, such as the trans

plantation

were associated

of development in animals whose corpora lutea were maintained (Asdell,

sterile copula

by hysterectomy, repeated

tions, or the injection

of anterior

Hammond, and Salisbury,

extracts

pituitary 1933).

Castration can usually be performed with impunity

during pregnancy in the guinea pig, maintenance animals

of the

which

gravid

state

continued

have

so far

as the

concerned.

is

to term

In

following

mechanisms responsible for the pregnancy

extirpation of the ovaries, normal mammary develop

changes in the mammae are still not entirely clear.

ment has been observed (Herrick, 1928; Nelson, 1934). In the human also the evidence is quite convincing

hormonal

It

is likely

different

that the several

degrees

Of

factors involved

importance

in

the

assume

different

mammals. Hildebrandt

that the ovaries are not the trophic genital

(1904), on the

basis

of clinical and

stages.

organs,

except

Halban cited in

perhaps

center for the

during

1905 several

the earliest

cases of bilateral

veterinary observations, was the first to propound the

ovariectomy during pregnancy in which normal mam

theory that the products of conception produce a sub

mary

4

development

and

lactation

occurred.

Many

MAMMARY GLAND OF THE RHESUS MONKEY in whom

continued

Pregnancy

day of gestation.

35th

uneventfully

month,

and

limits during

occurred

lactation

preg

following

Hartman

(1941)

reported an uninterrupted as early as the 25th

gestation1 following operation

day, and more recently this experiment was confirmed

Corner (personal communica

by

2

which

but the

produced

are

large amounts

of estrogens

this period almost cer—

during

in the placenta. This organ

tainly originate

thus

additional cases

by

tion, 1943). As in the human and the guinea pig, normally in the mammary development proceeds as indicated ovaries, monkey in the absence of the

following observations.

Monkey

no.

pregnancy.

Histologic

on the 46th day of examination of the mammary

revealed

gland at parturition

pregnancy.

of The

still uncertain, for

has

complete development of

during

role of progesterone

not been

possible to recover pregnanediol

from the

macaque’s urine (Marker and Hartman, 1940). Evidence from other sources has pointed to the placenta as the principal mammary common

organ responsible for the

of pregnancy.

growth

Gynecomastia

in patients with testicular tumors

finding

which contain chorionic elements. In the comparable in the female, full

of chorioepithelioma

development

breast

and lactation may occur in the

of corpora lutea (Fischer,

absence

1909).

(Selye, Collip, and Thomson,

rats

In pregnant

1935b;

Leonard,

This picture differed

1945) and mice (Newton and Lits, 1938) the mam mary glands have been maintained and have con

detail from the histologic pattern en

tinued to develop following castration and removal

the lobulo-alveolar

system,

including

and numerous mitotic figures. in no essential

precise

condition

457 was castrated

hormones

mammotrophic

a

stages.

the

of pregnancy,

it

by

bilateral ovariectomy performed at various

turbed

in

of the increased androgen titer

probable source

the

is

undis

rhesus monkey pregnancy has been

the

later section.

indicated as the chief although not the sole source

parturition.

In

as will be demonstrated in The adrenals have been regarded as

singly or in combination,

is

last

term,

to

nanediol excretion was within normal the

both ovaries

is

patient of Young (1941) were removed at about the

a

such cases have been observed since then, for example, the

activity

secretory

countered at term in animals with intact ovaries.

or destruction of all the fetuses,

Monkey no. 466 underwent bilateral ovariectomy on the 3rst day of gestation. Mammary development re

remaining intact. Even after hypophysectomy during

of pregnancy was per

formed on monkey no. 567 on the 35th day.

Abortion

Recent observations

interest

Dorfman in

this

the rhesus

These

the

a

attained during

an ovulatory menstrual cycle, rapid involution the

pregnancy

interrupted

as early as

In monkey no.

after conception.

occurs month

636 pregnancy was

abdominal hysterotomy. terminated 0n the 36th day Mammary biopsy at this time revealed well developed lobules

of

moderately

dilated

alveoli,

and

dilated

blood vessels coursing through the interlobular stroma

and androgens during pregnancy in

(fig. 44, 8). Fourteen days after operation, biopsy Shrinkage of of the mammary gland was repeated.

monkey.

Removal of the fetus

abdomi

nal hysterotomy, in addition to castration, was found to have

develop

significant

normally

in the urinary titers

authors demonstrated an increase of both estrogens

and Van Wagenen connection.

in early pregnancy

no significant effect on these hormonal levels, placenta was left undisturbed.

androgens are effective mammotrophic

Estrogens and agents,

either

a

1This animal was found subsequently to have fragment of ovarian tissue adhering to the uterus. The corpus luteum of preg nancy, however, had been removed in its entirety, as was proved '- serial sections.

the lobules had occurred, and the blood vessels

now quite inconspicuous

(fig. 45,

pl.

of

by

(1941)

are

undergo

ment beyond that which

by

fully developed and lactating organ. by

revealed

a

occurred on about the 87th day, 52 days after operation. Examination of the mammary gland 10 days later

to

8). This

were

regres

sion of the gland was comparable to that which was observed

following

ablation of the corpus luteum in

nonpregnant animal.

When pregnancy was interrupted stages, secretory

at somewhat later

changes representing

a

containing

ovariectomy with removal of the ovary the corpus luteum

and Allen, 1942) and guinea pig (Desclin, 1939). Despite the failure of the monkey’s mammary gland

pl.

Unilateral

in

continued

has

in the

I

of intact animals near term.

Beck, 1939; Newton

growth

only the placentas

mouse (Newton and and Richardson, 1941; Gardner

fashion

is

seen in the mammae

in all respects to that normally

fairly

mammary

normal

is

complete development, comparable

pregnancy,

a

revealed

140 days

of the gland at

if

mained unaffected, for examination

if

'

26

modified form

MAMMARY GLAND OF THE RHESUS MONKEY of involution.

of lactation appeared before the onset

hysterotomy was performed

Abdominal no.

on

680

the

day of

60th

on monkey and

pregnancy,

the

The histologic

products of gestation were removed.

picture of the mammary gland at this time is shown in figure 46, plate 8. The lobules were well developed and

alveoli

the

dilated,

were somewhat

was no evidence of secretory

but there

activity. Two days after

the operative abortion, mammary

biopsy was repeated

(fig-47, pl. 8). Secretory changes were now unmis in the cells as evidenced by marked

takably present vacuolization,

alveoli were distended to several

the

27

p the time from conception, and b and k are constants.

Gaines (1914)

has also shown that the transfusion

a temporary inhibition

We

of the secretion of milk.

have had the opportunity

to study the histologic

picture in the mammary gland of a pregnant monkey shortly after the cessation animal.

of nursing

activity by this

no. 117 was pregnant, near term, when received into the colony on April 12, and was still

Monkey

result of a previous

as a

lactating

Although milk was April

refused to

she

16,

expressed

from

on

On

nurse her offspring.

times their former size, and the products of secretion

May 8, about 26 days after weaning, tion was performed,

the

pregnancy.

her breasts

could be seen in the lumina of the alveoli.

Secretion

of

blood from a pregnant into a lactating goat results in

Caesarean sec

animal was killed,

and the

sections

the

second half but not the

first half of pregnancy (Loeb and Hesselberg, 1917b). In the rabbit, lactation follows Caesarean section after

(fig.

48,

presented

a

lowing abortion during

8)

mammary glands were obtained for study. Histologic pl.

occurs in the mammary glands of the guinea pig fol

rather bizarre

appearance that was not quite duplicated in any of the other specimens.

In many of the lobules lactation

about the 15th day of pregnancy (Bayliss and Starling, 1906); and in the mouse, hysterectomy as early as

was still in progress: the alveoli were large and irregu

the 11th day of pregnancy is followed by milk forma

the cells

tion within 48 hours (Bradbury, 1932). These observations bring to the fore the old prob

within the alveoli. In other lobules early changes could be seen, with desqua mated sheets of alveolar cells lying free within the distended alveoli. In still other lobules, and even in

held

in

which that

during

abeyance

Turner

have

nancy.

Meites

and

held on this subject and concluded

been

the lactogen-producing

overrides

progesterone

effects

pregnancy.

recently examined the different views

(1942)

(on the pituitary) of estrogen during preg-. Even in cases where lactation is established,

it is a well known clinical and veterinary fact that a of milk

supervening pregnancy results in a diminution Gaines and Davidson

production. pressed

(1926)

have

ex

this phenomenon by the mathematical formula

di/zlp=be"’, where i

the decrease

represents

in yield,

many of the interalveolar

ruptured;

septa

appeared to be actively secreting, and milk

was present

involutionary

was

different regions of the same lobules, involution well

advanced:

secretory

activity

had

the

ceased,

alveoli were small, some even collapsed, the cells were small and the nuclei pyknotic,

and considerable in—

teralveolar connective tissue had returned and was in

All

filtrated with moderate numbers of round cells. these

changes can be seen in the single microscopic in figure 48. Involution but not prevented,

field shown been

modified,

had obviously by

lem concerning the mechanism by which lactation is

lar, with

coexisting

the

pregnancy.

LACTATION activity

and finds overt expression in the production only

represents

an accentuation

of processes

of milk which

were initiated in the mammae as early as the middle

When

placenta

is

of pregnancy.

this substance 3d

inhibitory

removed, increased

hormone become on the

the

effect

of

the

amounts of lactogenic

mobilized, and in parturient women

can be recovered

in the urine beginning

or 4th postpartum day (Hoffmann, I936),

with

synchronously

the

of

establishment

lactation.

Although milk secretion may

mally

birth

at

tained

in hypophysectomized

lactation

functioning

occurs only

full-scale

set in

wall,

of

pituitary gland (Selye, Collip, and Thom

parturition

glands,

sus

in the presence

son, 1933) or adequate substitutional therapy. The secretion of milk begins within the first

after

nor

animals,

a

in the secretory

which

rapidly

in

the

previously

monkey. lay

flat

enlarge, and when

2

increase

days

The mammary against the lactation

is

The remarkable

Of the mammary glands which occurs after parturition

chest at

its

MAMMARY GLAND OF THE RHESUS MONKEY

28

height,

milk-filled

the

breasts

in large folds

hang

below the costal margins

The general

have

are

to all mammals.

mammae

of several monkeys

lactation.

The lobules were large and the alveoli

various periods of

positions

or combined

various

aspects

of the different theories.

We have examined the

common

at

taken one view or the other, or have assumed

intermediate

(fig. 11, pl. 2). histologic features of lactation

to those who have regarded the secretion

According

of milk as a purely vital activity, no further increase

in

the

actual number of glandular

cells occurs after

greatly distended, for the most part, with a faintly

parturition.

staining, granular secretion (milk). Very little stroma was present in the glands. In many places the inter

cellular proliferation

alveolar septa were ruptured

theory. The larger number of investigators, hoWever, have recognized the need for cellular replacement dur

jected

into

the

contained

septa

coalesced

numerous

and the free ends pro small

The

lumina.

alveolar

blood

a

vessels,

their

Indeed,

to demonstrate

inability

in lactating glands

has been one

of the points of evidence raised in support of their

course of lactation.

ing the

Guillebeau

(1916), for

among the latter.

example, basing his conclusions on histological con siderations and on mathematical calculations of the

(1898) noted numerous eosinophiles in the interstitial tissue of the mammary gland of the post

milk constituents, pointed out the necessity for replace ment of gland cells during lactation in the cow and

few connective-tissue cells, and occasional leukocytes. Eosinophiles

appeared prominently

Michaelis partum

pig, and more recently others have

guinea

described increased numbers

of eosinophiles

interalveolar and interlobular

connective tissue of the

albino

lactating

(Emmel,

rat

in the and

Weatherford,

Streicher, 1926) and bat (Ieffers, 1940). The former authors expressed agreement with the idea of Rauber (1879)

that leukocytes contribute

constituent

a definite

of milk.

to the composition

cellular

In all our

goat. gland shortly

Mitoses still occur in the mammary after parturition.

They have

been

observed in the

guinea pig, cat, rabbit, rat, and cow; and we have seen mitotic figures during the early days of lactation in the monkey. They then became rare, however, and soon they could not be demonstrated at all. This is in accord with most of the observations on other a few workers claim to have demon

specimens the cells which lined distended alveoli were

species, although

flattened out. In regions where the alveoli were not

mitotic figures in the mammae at later stages of lactation. Having failed to find mitoses in an

distended,

the

cells

appeared larger and elongated,

strated

The

examination

of hundreds of microscopic preparations

nuclei were large and contained large, single, distinct

’of lactating

glands,

and contained abundant

vacuolated cytoplasm.

The nuclei tended

nucleoli, and granular chromatin.

possibility

Nissen

in

1886

of direct cell division.

suggested

the views

Divergent

into the lumen of the alveolus. At the height of lacta

concerning this possibility were expressed in the litera ture for many succeeding years, various authors either

tion evidence of secretory

affirming

to be located basally, but in many places

they bulged

activity could be seen in the

or denying

epithelium lining the small ducts as well as the alveoli.

clear division

Duct secretion

species.

the cow, cat, dog, guinea pig, and

including

rabbit (Richter,

described in many other

1928).

The nature of milk secretion subject

of

wide

differences

regarded the process

long been

has

the

type of

When direct nuclear division does occur, it is rarely if ever accompanied by division of the cell body

Langer

(1852),

as a result of amitosis.

opinion.

Virchow

epithelial cells.

(Conklin,

1917).

Binucleate cells are thus produced Such cells have been observed

cells played no part in lactation; secretary. Rauber

alveoli

and there underwent

eventual transformation

glands of the guinea pig,

regarded

the

cat, dog, rabbit, mouse, bat, and human, even

emphasized

the

thin sections.

he

importance of the leukocytes. These, he held, invaded the

different

Amitosis occasionally takes place in cells which have

in the lactating mammary

as purely

of

no genetic value, such as those of the ovarian follicular epithelium, placenta, and outer layers of the epidermis.

on the other hand, maintained that death of epithelial

process

glands

as a physiologic

of

(I862) fatty degeneration, the milk globules being set free by the disintegrating

the occurrence of amitotic nu

the lactating

degeneration

and

into milk. Subsequent authors

in very

Double and lobulated nuclei have like

wise been encountered in the lactating glands of our rhesus

monkeys (fig. 49,

pl.

species,

has also been

in

8). These nuclei had the

same general internal structure as single nuclei.

Ami

MAMMARY GLAND OF THE RHESUS MONKEY merely to distribute

nuclear material through

the

thereby results, a factor which may be of significance

phenomenon, but serves

tosis is not a true divisional

29

in the synthetic and secretory

a

greater region of the cell. Increased nuclear surface

activity of the cell during

lactation.

INVOLUTION The

milk secretion which occur

rise and decline of

in

and end of lactation have been re

at the beginning

which has

garded as a type of growth and senescence

When

Turner, and Ragsdale,

(Brody,

rate

1924).

Turner,

and

Ragsdale,

milk secretion limiting

but the exact

substance

with lactation.

associated

the rat (Myers and Myers, 1921; Maeder, 1922), and the glands were found to have returned approximately to their resting (virginal) state by the end of the 2d or

of

3d week after weaning. Involution was found to be almost complete in a dog 40 days after parturition

nature of this

The role of

(Turner and Gomez,

factors

indicated

Halban

of the adrenals

the importance

glands of non-nursing

atrophy which

follows castration, attributing Ernst

the ovaries.

between

parallelism

puerperal

and

both to

postmenstrual

By and large, results of experi

changes in the breasts.

1933b).. Complete occurred in a goat within 51/2

months after the suspension of milking (Turner and Reineke, 1936). In each of these species the lobulo

of

attempted to establish a

(1925)

(Turner and Gomez, involution

mammary

women to the

the absence of the protective and regulatory influence

of

the young

also.

compared the puerperal involution

(1905)

the mammary

(Turner and DeMoss, 1934), and com guinea pig 100 days following removal of

plete in a

pituitary

the

1934), complete in a cat 80 days

after weaning

has already been mentioned, and abundant evidence has

‘

alveolar system underwent complete atrophy and only the duct system remained. The exact duration of the involutional

changes following parturition or lactation in the human has not been determined, but Deaver and McFarland

(1917)

have stated

mental efforts to demonstrate an effect of the ovaries

extend over months or even

on the postpartum involution

rupted by recurrent pregnancy.

have

not

of the mammary glands

Kuramitsu and Loch

impressive.

been

were only able to demonstrate a less intense

(1921)

leukocytic invasion of the glands of rats and guinea pigs

following castration.

Williams

state.

reaction, the

importance are the hormonal

paramount

and the length of time required

of involution

are

never been demonstrated.

has

or

in the

that

is determined by the concentration

substance,

hypothetical

by a chemical

is limited

speed of which

Of

factors

in this process.' It has been suggested

involved

a

is complete (Brody,

Several

1923).

following parturition

differences occur only

Important

In the mouse, regression is complete 5 days after parturition (Williams, 1942b) and 13 days after wean ing (Cole, 1934). Involution has been well studied in

tion of milk begins to wane, the rate of decline re maining constant until involution

species

for the glands to return to their prepregnant

the secre

a certain stage of lactation is reached,

occurs in the mammary

which

of various

weaning.

the unique property of being renewed following every pregnancy

the involution

glands

(1942b)

more

years

that they may when

The present studies on involution are based at various days

upon the mammary stages

not inter

in the monkey

glands of 22 animals

from the onset

of lactation to 127 monkeys, to

after weaning, and in non-nursing

In many instances only one

recently found that neither castration nor the injection

109 days

of

specimen was obtained from an animal, but the most

or

estrone,

in

progesterone, and testosterone,

various

mammary removed

combinations,

involution on

the

altered

mice

studied in castrated perhaps during

function

course of

litters

day.

were

Although

of the mammary glands has not primates, it is unlikely

their ovaries play a significant except

the

whose

postpartum

10th

puerperal involution been

in

either singly

the

is at a very low

that

role in this process,

later stages, since ovarian ebb

following parturition

in man and monkey. Morphologically,

certain similarities have been noted

instructive

postpartum. material

resulted from

the serial mam

mary biopsies on the same animal at various stages of involution.

This was accomplished in

most complete series

being obtained

8 cases,

from

the

the fol

lowing: Monkeys nos. 601, 654, and 690 (see section on preg nancy). Monkey no. 614. Stillbirth on r5oth day of gestation. Mammary biopsies on days 9, 25, 36, 66, and 109 post partum.

MAMMARY GLAND OF THE RHESUS MONKEY

gland presented lution

proceeded

different

at

in

each

the same histologic picture, for invo

often progressed at a diflerent

The following description

lobule.

rates

In addition, not all parts of

on a typical or average

case.

in each

rate

is therefore based

Special features of in

volution and important variations will be given sepa rate mention. Gross mounts of mammary

specimens from non

nursing animals showed the lobules in a state of en gorgement

for approximately

period

alveoli

the

stagnant

the

2d

week

The histologic appearance of such

lumina. shown

in figure 52, plate

which

biopsy specimen Obtained from

gland

represents

monkey

no. 654 at

the time of weaning on the 4th postpartum day. The rapidity Of the involutionary changes during the first

weeks

clearly shown in

biopsy specimen

from the same animal 20 days later (fig. 53, pl. 9). The lobules and their component alveoli were dis tinctly smaller and there was

corresponding increase

in the amount of loose interlobular connective tissue. Much of the intra-alveolar secretion had disappeared, but secretory

vacuoles were still present in most of the

Great variation

cells.

was noted in the size

of the

nuclei; most, however, were considerably smaller than

in size and the interlobular

stroma

in the lactating gland.

on the 9th postpartum day. Despite the beginning regression of the lobules, the ducts were still distended, even bulging

the

products of their secretion could be seen in the alveolar

lobules

evident:

Figure 50, plate 9, shows a typical gland

reappeared.

in many

secreting and

the

became

changes

began to decrease

During

products.

secretory

involutionary

During this with

2 weeks.

and ducts were distended

were ruptured

a

glands animals.

of the

which

were actively

cells

a

mammary difierent

involution

thin scpta

The

3

and postlactational

Postpartum

rated places.

a

weaning.

As

were large and the alveoli were distended and sepa

in places,

with their retained contents.

took

They were oval in

A

and

shape

moderate, diffuse cellular

in stain. filtratiOn, composed chiefly of round cells, was present a

after

in

described in the preceding section, the lactating lobules

9,

Monkey no. 665. Baby weaned 42 days after parturition. Mammary biopsies on days 0, I3, 28, 44, 78, and 127

description of the histologic changes during

a

108 after weaning.

is

and

A

volution properly begins with the lactating gland.

is

Monkey no. 652. Baby weaned 112 days after parturi tion. Mammary biopsies on days 0, 13, 28, 4'4, 78,

by

30

deep

in the lobular stroma, with denser accumulations some

in

regions than in others.

During the next 2 weeks involution progressed rapidly and the lobules returned to a fraction of their former

in the amount of glandular parenchyma.

size. The ducts, however, were still dilated at the end

of this period the lobules were still smaller and the

of this period, their diameters often exceeding those of the lobules. Subsequent changes progressed at a

alveoli fewer. Most of the latter were collapsed; those

relatively slow rate, as judged by the appearance of the gross mounts. By the end of 31/2 months involution

of the cells contained vacuoles,

was complete.

present

Mammary

atrophy of this degree,

castrate

condition

(fig.

51,

9). however, did not

following parturition

subject to considerable varia

tion.

is

The return of ovarian function

If

occur in every case.

the ovaries are slow to resume

control of the

the end

pyknotic.

Increased

of

numbers

round

density of the connective tissue had increased, both within and between the lobules. Particularly striking was the increase

in connective tissue about the ducts

(fig- 54, P1-9)

The involutionary the

month

which occurred during

changes

represented

continuation

and puerperal

then mammary

reduced in size, so that they consisted of only

the other hand,

small alveoli with collapsed walls.

persists,

menstruation

may

On

occur relatively soon after parturi—

made

up of shrunken, inactive cells.

When this occurs, mammary involution

decreased

or growth

is

cells

is

tion, indicating an early resumption of ovarian activity. interrupted

renewed, depending upon the condition

of the gland and the intensity of ovarian stimulation.

persisted

throughout

numbers.

the amount of dense

rounding

A

the

the few

The latter were Scattered

round

stroma, but in greatly

further increase

was noted in

connective tissue, especially sur

the ducts (fig. 55,

pl.

amenorrhea

of

already described. The lobules were greatly

processes

continues unaffected.

were

cells

in the interalveolar stroma. The amount and

secondary sex organs, and the uterus remains small involution

Few

a

the

At

and the nuclei were

a

atrophic state which frequently

resembled

pl.

returned to a delicate,

occurred

decrease

that still remained patent had only small lumina.

3d

Both the lobules and the ducts had

During the next month further

9).

MAMMARY GLAND OF THE RHESUS MONKEY development

constituted one of the constant and prominent

factors

composed chiefly of round cells, but polymorphonu

might find that in one of two neighboring

clear leukocytes and large mononuclear

varied

a

histologic

picture

This irregularity of involution

lobule.

in figure 56, plate 10, which represents

dense cellular infiltration was present. alveoli

were greatly

still present within (1937a, 1937b),

gland of

dilated

the lumina.

In other regions

Hesselberg and Loeb also called attention to

the persistence of areas in which the alveoli have the

McFarland

has

(1922)

even

In

the human,

described the so-called

residual

lactation alveoli, structures which

involute

because

of obstruction

to the

This was held

ducts and alveoli.

subsequent cyst formation

phases

failed to

outlets of the

to be the basis

in the breast.

for

The irregu

larity of retrogression and the persistence

of dilated

distribution

considerable variation

was en

to the time and height of the

its duration,

the mammary

through

cellular infiltration

As with the other

2d month.

the

peak of the cellular infiltration,

and secretion was

characteristics of the secreting gland.

until

of involution,

a biopsy speci

describing the retrogressing mammary

the guinea pig, have

centration

countered with respect

on the 49th postpartum day. In some of the lobules the alveoli were completely collapsed and a

weeks of invo

lution, but did not usually attain their maximal con

is well shown

men

the

interalveolar stroma within the first

and its

A

lobules.

typical

shown in figure 59, plate 10,

biopsy specimen obtained 44 days after weaning. The foregoing description of mammary involution upon animals which did not nurse their off

based

spring or in which nursing was interrupted soon after

This description

parturition.

also applicable quali

tatively to animals whose young were weaned after months or more of suckling. of the

glands

Study of the mammary

latter group

resulted in the distinct

impression, however, that their involution

progressed

contrary to somewhat more rapid rate. This recent observations Williams (1942b), who found at

is

Such

even be observed in different parts of the same

cells could

cells appeared in the

is

secretion.

re—

is

tained

the alveoli were still distended with

These

also be demonstrated.

2

retrogressive changes had occurred, whereas

in the other might

of

periods

by

marked

prolonged

involution,

is

after fairly

The cellular infiltrate was

involution.

a

even

lobules,

in mammary

a

contrast with the rather uniform

of the mammary gland which occurred during preg nancy, involution was an irregular' process. Thus one

3

In

31

which occurred in the

that the postpartum involution mammary

glands

of

in the complete

mouse

the

of suckling was more rapid than the involu

alveoli with retained secretion in the monkey’s mam

absence

mary gland were only temporary aberrations in the

tion which occurred after varying periods of lactation.

amount

the

of

glandular

substance.

The rapid decline in vascularity which followed the cessation of lactation caused atrophy of the paren chymal elements, with

shrinkage

of the alveoli and

resorption of the cells.

This may

be regarded

Following

atrophy of disuse.

asan

the rapid death of some

aborted

is

established involutionary

no. 690 aborted its fetus on the pregnancy, fetal death having been

Monkey

processes. 106th

day of

caused

within

the preceding

days

the injection of

into the amniotic

substance

(Thorotrast) Biopsy of the mammary gland revealed

into the lumina.

ing organ with no signs of involution.

lying

singly

or in sheets

within both

the

pl.

seen

specimen obtained

weeks later,

In

lactat biopsy

histologic picture

comparable

fashion, as can be seen in figure 58. Liquefaction absorption of these cells was probably aided

cental function had been disturbed in the latter animal

by

and the

leukocytes which migrated into the lumina. Despite

the

fact that its

precise

significance

observed.

approximately occurred,

has

not been established, leukocytic invasion of the lobules

no. 449 at parturition was The inference seemed justified that pla to

gressed

and

during

that in

2

10) and the ducts (fig. 58, 10). Masses of duct epithelium were lost in similar a

alveoli (fig. 57,

pl.

be

a

sac.

2

of the alveolar cells, large numbers of them sloughed Here these desquamated cells could

449

of the maternal mammary gland

this time revealed well

foreign

may

no.

macerated fetus on the 101st day of preg

nancy. Examination at

involution Monkey

a

in

were responsible for the

occurs.

parturition

a

least two mechanisms

reduction

before

begin

by

prepregnant state.

disturbed, as manifested

fetal death in utero, mammary

3

plete, all parenchymal structures had returned to their

At

When placental function

was com

a

When involution

by

process.

a

involutionary

weeks before emptying of the uterus

that mammary

involution

had pro

the interim.

Typical involutionary

changes were observed in the

MAMMARY GLAND OF THE RHESUS MONKEY

32

glands of animals following

mammary

the interrup

were present. The lobules were smaller

of involution

tion of pregnancy at earlier stages. In monkey no. 680,

than at operation, the alveoli were collapsed, an in

for example, abdominal

creased

hysterotomy was performed

amount

of connective tissue

and a cellular

were present in the stroma, and desqua

on the 80th day, and in monkey no. 636 on the 36th day. Mammary biopsy was repeated 17 days after

infiltration

operation in the former and 14 days after operation in the latter animal. In both instances definite signs

activity, which was present 3 days postoperatively in no. 680, had largely subsided by the 17th day.

mated epithelial cells lay free in the ducts. Secretory

EFFECTS OF CASTRATION The importance of the ovaries for mammary de velopment is firmly established, but the changes which of

result from

removal

understood.

Little attention

the

ovaries are has

of castration on the mammary

effects

but poorly

been given to the gland.

Mam

did

not occur in rats (Turner and Schultze, 1931) and guinea pigs (Ebhardt, 1928) fol lowing ablation of the ovaries. Observations on the mary

atrophy

human are scant and contradictory. detected

Alterthum (1891),

large majority

of the specimens were from monkeys

during pregnancy.

animals were castrated the

untreated.

effects

In order

of castration

follows: Monkey no.

40 per cent

however, were the glands examined histologically.

The only observations on the mammary glands of castrated monkeys are those of Aberle (1934a). She

of

5 controls.

There was no significant differ

area between the two groups.

Araonuc The progress of postcastration atrophy was observed in both the gross mounts and the histologic sections of the biopsy specimens.

A

typical series is shown in

figures 60 to 67, plate 11, which represent

mammary

specimens obtained from monkey no. 592 at various stages after ovariectomy. On January 1,_194o, castra tion and biopsy of the

mammary

gland

were per

formed.

The well developed mammary lobules were

separated

by only small amounts of connective tissue

(figs. 60, 64).

Definite

shrinkage of the lobules oc

at various

and extending through

increased in size. In none of these cases,

in mammary

the mammary

moval of the ovaries. On these 6, a total of 21 biopsies

about 60 per cent of those patients who experienced

ence

re

intervals following surgical re

of 116 patients, Pfister (1898) observed breast changes in 50 per cent after castration. Atrophy was noted in

those

few

study systematically

itself upon

were performed, beginning

compared the glands of 4 animals whose ovaries had been removed 7 days to 6 months previously with

to

A

Many

glands, serial biopsy specimens were obtained from

half their former size) and the areolas became lighter in color after bilateral ovariectomy. In a clinical study

the breasts

prepara

tions subsequent to removal of the ovaries.

6 animals

changes, whereas in the remaining

specimens

were treated with various hormonal

which

on the other hand, found that in 15 cases the nipples and breasts grew significantly smaller (less than one

breast

mammary

155

from 85 castrated mature female animals at intervals ranging up to more than 4 years after castration. The

mained

no changes in the breasts, nipples, or areolas

of 18 young women after castration. Keppler

Our \material includes

which were obtained either for biopsy or at autopsy

at the time of operation

the following 2% months as Biopsy, day: after castration

592 620

. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . ..

o, 45

623 660

. . . . . . . . . . . . . . . . . ..

o, 20, 50

0, 10, 3o, 58

. . . . . . . . . . . . . . . . . ..

0, 14, 29, 62, 76

673

. . . . . . . . . . . . . . . . . ..

o, 37

687

. . . . . . . . . . . . . . . . . ..

o, 14, 29, 62, 76

The structural changes which were observed in the mammary glands after castration were of two general atrophic and proliferative.

types,

These occurred con

currently in the same glands. CHANGES

curred within 10 days (figs. 61,

Biopsies were re

on the 30th and 58th days after castration. These specimens revealed a progressive diminution in peated

size of the lobules, with a corresponding the

relative amount of interlobular

66;

63,

Microscopically,

increase

in

stroma (figs. 62,

the alveoli were fewer

and smaller and their walls gradually collapsed. The alveolar cells likewise

diminished

in size and their

constituent nuclei became pyknotic.

In

some

cases, such as that just described, the out

MAMMARY GLAND OF THE RHESUS MONKEY

connective

tissue.

shown in biopsy specimens ob

is well

pl.

pl.

tained from monkey no. 623 at the time of castration (fig. 68, 12). 12) and 50 days later (fig. 69,

PROLIFERATIVE

with this generalized epithelial atrophy

Concurrently

and stromal sclerosis,

localized

hyperplastic

nodules

developed throughout the mammary glands of mature castrated females.

These

which stood out

islets of alveolar tissue

circumscribed

in sharp contrast from the gland

nodules consisted of well

(fig.

the

pl. 12). The development and tumors have been described in

70,

a

structure of these

and will be referred

paper (Speert, 1940c) to only briefly here.

previous

Nodule formation occurred

as early as 29 days after

tumors

were

monkey no. 623.

This

of the tissue and

formation

month

after castration.

in causing

their

The tumors appeared grossly

injections.

round or oval discoid masses

as white, opaque, dense,

ranged from

to

6

lay in the plane of the mammary 1

which

mm. in diameter. Great variation

a

was observed in the number glands only

solitary

tumor

lobules.

atrophic

In

of nodules.

some

was present, whereas

others contained 20 or 30, irregularly the remaining

gland and

spaced

Histologic'

among sections

was begun during

the first had ap

treatment was ineffectual

regression or in modifying

Of but

contained nodules, all

43 specimens which

the

were from castrated

animals. These

the specificity

of the nodular

ovarian

a

period of seriously altered ovarian (partial

amenorrhea). of these animals were indistinguishable the castrates

(fig. 71,

which

occur with great frequency

women

around

and

beyond

Lobular irregularities

the glands

received no hormonal

ment after operation. Mammary

treat

nodules were usually

were pregnant at the time of operation

a

in

which

series

the remainder

of 57 other castrated

animals,

absent

of which

were treated

with

2

a

Tumors appeared in

micro normal

breasts

during this period (Geschickter,

(1904), von Saar (1907), and Dietrich

various

mammae, function

are

intimately

(Buschke,

Mammary

dependent

mice

Little,

194117).

1941;

Gardner,

with nodular

(Fekete,

and its esters, progesterone, and desoxy

In

the rhesus monkey,

by

cortex and occurred in animals of

testosterone

upon

gonadal

tumors have also been observed in un

treated ovariectomized associated

diethylstilbestrol,

changes have been

1933).

hormones after removal of the ovaries. The hormones estrogens,

mani

and almost physiologic

included

various natural

regarded

and cystadenomatous changes as Similar

Tietze

1943).

(1926)

observed in the apocrine glands of the axilla in 40 per cent of women over 51. These glands, like the

of

and

of age.

demonstrated

can be

proliferative

which

menopausal

scopically in more than one-third of clinically

for old age.

18 castrates

in the breasts

the

failure

in the alveolar cells.

from those of

on the spayed monkey with certain pathologic changes

festation of ovarian

of

glands

12). tempting to compare the present observations

proliferative

Mitotic figures were

large

hypophysectomy,

The mammary

cysts,

resemblance to that of

vacuoles were usually present

non

animals, however, gave evidence of having

castrated

nature, the microscopic

abundant and secretory

exceptions change in

relation to absence of the ovaries. Five of the

appearance bearing

normal mammary parenchyma.

either

their gross or microscopic structure.

revealed their adenomatous close

was effective

of these

Once the nodules

peared, however, hormonal

is

hormonal

to dissection.

of the nodules when treat

ment in adequate dosage

It

4

mary glands of other animals which received various

Each

acetate.

in preventing

undergone at least

after castration in the mam

clear in

was mani

an increased toughness

its resistance

corticosterone

structure or function

years

sclerosis

CHANGES

the longest ppstcastration interval represented among the glands from untreated animals, but nodules per as long as

of

degree

fested even in the fresh state

found as long as 18 months after spaying. This was

sisted

discernible in the

photographs of the latter, were unmistakably

challenge

of the ovaries, and definitive

removal

regions of

surrounding

changes, on the other hand, scarcely

6

This change

interlobular

the

a

of

density

6

and

These

hyperplasia a

striking,

by

less

pl.

In others this was

atrophy.

attention being drawn rather to the increased amount

by

epithelial

The lobular atrophy, although distinct, was not as great as that observed in monkey no. 592. The stromal

6

standing feature of the postcastration changes was the

33

Woolley,

and

tumors

were

of the

adrenal

high cancer strain.

contrast, spontaneous mam

MAMMARY GLAND OF THE RHESUS MONKEY the

month

3d

went a decided increase

glands under

the

in thickness.

Great hyper

lobular

The

stroma.

the end of the

increase

3d

During

thickness.

by

24

trophy of the lobules occurred, so that in the gross

to the rapid multiplication

mounts

An

interlobular

less

mained visible. The alveoli became

stroma

re

enlarged to such

an extent by the 4th month that they could be dis tinguished at the periphery of the lobules, even at low (fig. 37). The blood vessels also became more prominent as a result of their increased caliber.

increasing

attested

number

more

a

progressively

in size of the lobules

month was due, in the main,

rapid

of the alveoli

(fig. 40).

of mitotic figures further The rate of proliferation.

alveolar cells also appeared larger. Superimposed upon activity were clear-cut evidences of

this proliferative

magnification

secretory activity in the mammary gland at this stage

Specimens obtained at subsequent stages of pregnancy

of pregnancy. The nuclei were basally located, many cells contained supranuclear vacuoles, and in others

revealed still further increase in thickness of the gland.

secretory

The lobules

the lumina of the alveoli. The majority of the alveoli

progressively larger, chiefly

became

be

The individual

cause of the dilatation of their alveoli.

were more

or

jutted from the cell margins into distended

less

and contained

small

the lobules as term was approached, despite the virtual

amounts of colostrum (fig. 40). This secretion, which was also present in the ducts, presented an amorphous

replacement of the interlobular

appearance microscopically

stroma by

the en

pl.

larging lobules (fig. 38). The histologic basis for the gross changes observed in the mounts was revealed in microscopic sections of the same specimens (figs. 39—42,

of lobular growth during the was confirmed.

7). The paucity

1st month of pregnancy

Glands which were poorly developed

and gave no evidence of

desquamated epithelial cells or leukocytes, which are commonly observed in the colostrum of other species. Secretory activity was well established in most glands by

alveoli were clearly distinguishable at the periphery of

processes

the beginning of the 4th month of pregnancy. Some variation was encountered in this respect, how

In monkey no.

ever.

690, for example, there was no

at the time of conception still showed no better lobular

evidence of secretion in histologic sections of the mam

development at the end of

mary gland at 106 days.

1

such glands after

of

sections

month’s gestation showed lobules

which were just beginning

to take form.

These were

Biopsies at subsequent stages of pregnancy term

revealed

secretory

a

a

month than was observed

in many nonpregnant animals. Histologic

activity.

continuation

up to

and accentuation

of

The lobules became progressively

larger and the alveoli became

sparsely spaced in an undifferentiated connective-tissue

with colostrum

stroma (fig. 39). The patent alveoli were formed moderately large cuboidal cells which contained large,

and the products of secretion distended the alveoli,

and relatively

little cytoplasm.

sional mitotic figures were seen. coursed numerous

Through which

blood vessels,

Occa

the stroma

supplied the

lobules with dilated capillaries filled with

blood

red

cells.

what larger and there

of cytoplasm

amount

Speci a

a

in

in the size of the lobules.

individual was

a

the

gradually

months.

months’ gestation revealed

slight increase

The alveoli and

3d

the 2d and

during

mens obtained after relatively

occurred at

proliferation

creasing rate

2

Alveolar

cells appeared some in the

relative increase

in the latter.

Mitoses

were

slightly more numerous but were still not conspicuous. greatest

impetus to glandular

manifest during the lobular

period, with

a

mendous

3d

The

month

hypertrophy

growth

became

of pregnancy. occurred

during

Tre this

resultant relative decrease in the inter

their

walls

became thinned

Mitotic figures continued numbers.

Vascularity

in

out

many

places.

in evidence in moderate

of the lobules became increas

ingly prominent with the approach of parturition. During the last trimester of pregnancy many glands contained an increased proportion

of eosinophiles in

the blood vessels. The significance of this finding not clear. Eosinophiles have been described in the

is

nuclei

distended

(figs. 41, 42). nuclei increased in size, but as term was approached

stroma and among the alveoli in the breasts

of the

human newborn, and they are known to occur in the adult breast

also.

is

round

increasingly

The cells and their

It

by

composed of small numbers of alveoli and were rather

present in the mammary

probable that these cells are glands of other animals as

well, for Ieffers (1940) has described them in the bat at the time of parturition.

Many authors who have described

the human mam

mary gland during pregnancy have commented upon the

presence

in every breast

of small lobules which

MAMMARY GLAND OF THE RHESUS MONKEY have failed to undergo the complete development of

their neighbors.

These

termed

have been

virginal

lobules, and their failure to respond to the hormonal

of pregnancy

stimulation herent

has

Recalcitrant

of this

lobules

structure.

were

sort

In

countered in the monkey. at

attributed to in

been

focal deficiencies in the glandular

never

en

mammary gland

every

or near term, all lobules were found

to have

under

gone complete and rather uniform development.

The mitotic proliferation of

the alveolar cells which

is responsible for the rapid growth

gland in early pregnancy

of the mammary

was described as early as

in the glands of dogs, rabbits, cats, rats,

and

stance

which

mammary

25

time causes growth

at the same

and

gland

inhibits

lactation.

By

developed this theory further, attributing

(1905)

of

ovaries and placenta, and the inhibition of

the

lactation to the latter organ. This theory has survived to the present day.

The early experiments of Lane-Claypon and Star ling (1906), Aschner and Grigoriu (1911), and Biedl and KOnigstein

( 1911), based on the injection of fetal into rabbits and guinea pigs, suggested the

extracts

mammotrophic

Subsequent

of this work,

In the rat, for example, mitoses are rare after the 13th day (Roberts, 1921). In 3

clusions.

human specimens which

sponsible for mammary

the

representing

Grynfeltt

4th,

studied,

(1936)

and last months of preg

6th,

nancy, no mitotic figures were found.

Our material,

an increased incidence of mitotic

by contrast, revealed

the

mammary development of pregnancy to the influence

fetus as the source of the

half of pregnancy.

clever

analysis of well known clinical observations, Halban

guinea pigs (Bizzozero and Vassale, 1887). In these species mitotic growth is restricted largely to the first

1887

of the

reinterpretation

the probable incorrectness of their con

has indicated

Attention

in particular

was later directed to the ovaries,

to the corpus luteum, as the agent re

during pseudopreg during pregnancy. Ancel

growth

nancy and, by implication, and Bouin mammary

stimuli. however,

(1911) demonstrated the identity of the changes of pseudopregnancy with those

figures in the mammary gland of the monkey during

which occur during the first part of pregnancy in the

the second half of gestation. Figure 43, plate 7, shows

rabbit (phase de développement gravidique).

an example of the frequency of mitoses at term. This

changes were attributed directly

biopsy specimen, obtained at 157 days’ pregnancy and 4 days before parturition, contained numerous mitotic

the corpora lutea, but were held to be of difierent

including three consecutive

five of which,

figures,

mitoses in the wall of an alveolus, are shown in the

The enlargement of the monkey's mam the later stages of pregnancy is the during mary gland result of continued mitotic p'roliferation of the cells

photograph.

of the alveoli.

as well as dilatation

plantation

experiments

(1906), and Stricker

of

Ribbert

(1929), the

Basch

(1898),

parabiosis

experi

ments of Ernst (1927), the nerve resections of Pfister (1901), and the injection of hormones, have established beyond question the endocrine basis of the mammary of pregnancy.

development widely

for

accepted

hormonal

many

This concept years;

yet

has

the

been

precise

mechanisms responsible for the pregnancy

changes in the mammae are still not entirely clear.

It

is likely

different

that the several

degrees

of

factors involved

importance

in

the

assume

different

mammals. Hildebrandt

origin from the secretory changes of the latter part of pregnancy (phase glandulaire gravidique), which were associated with the so-called myometrial gland (Bouin and Ancel, 1912). The extraovarian origin of the stimulus for mammary development during the latter part of pregnancy

of development in animals whose corpora lutea were maintained (Asdell,

basis

of clinical

veterinary observations, was the first to propound

and the

theory that the products of conception produce a sub

sterile copula

hysterectomy, repeated

by

tions, or the

of anterior pituitary

injection

Hammond, and Salisbury,

extracts

1933).

Castration can usually be performed with impunity

during pregnancy in the guinea pig, maintenance animals

of the

which

gravid

state

continued

have

so far

as the

concerned.

is

to term

In

following

extirpation of the ovaries, normal mammary develop ment has been observed (Herrick, 1928; Nelson, 1934). also the evidence is quite convincing

In the human

that the ovaries are not the genital

(1904), on the

in the rabbit was further

by the failure of attainment of the final phases

attested

Various experimental procedures, such as the trans

These

to the influence of

stages.

organs,

except

Halban cited in

trophic

perhaps

center for the

during

1905 several

the

earliest

cases of bilateral

ovariectomy during pregnancy in which normal mam mary

development

and

lactation

occurred.

Many

MAMMARY GLAND OF THE RHESUS MONKEY

34

mary cancer has not been observed, nor has it been produced experimentally with large amounts of estro genic hormone (see section on “Effects of hormones”). The pathogenesis of mammary tumors in the

following castration

breast

monkey’s

and gonadotrophic

Estrogenic

not

is

clear.

persist in

substances

the blood and urine of women after the natural meno

or

pause

surgical

removal

and

Salmon,

Goldberger,

Murphy,

Walter,

1939;

of

ovaries (Frank, Fluhmann and

the

1936;

Geist,

and Salmon,

and the urinary titer of 17-ketosteroids

1940),

after

increases

bilateral o'ophorectomy (Ross, Hamblen,

Cuyler, and

Baptist, 1941). In a strain of mice bearing adrenal tumors, castration caused a threefold increase in the

(Dorfman and Gardner,

excretion of estrogens Whether

1944).

phenomena have any significance for

these

our observations on the monkey is uncertain, nor do they

the focal

explain

activity in the presence mammary

occurrence of proliferative of generalized atrophy of the

The prevention

gland.

of postcastration and other

by ovarian

tumors of the macaque breast

steroidal hormones may be related to the ability of compounds

these

the hypophysis

to

changes in

prevent castration

(Clarke,

Albert, and Selye,

1942).

EFFECTS OF HORMONES During been

since many hormones have

the past decade,

available in chemically

pure form, it has been

possible to correlate certain mammary

changes, both

normal and abnormal, with specific groups of chemical compounds.

Foremost

hormones are those

mammotrophic

the

among

The biologic

of ovarian origin.

of the mammae. mary response

obtained a positive mam

Fellner

rabbits subcutaneously or

by injecting

intraperitoneally

of ovaries which con

with extracts

tained corpora lutea. Several investigators confirmed observations, using crude ovarian extracts,

these

little progress was made toward identification

but

of the

characteristics of the female mammary gland during

specific ovarian hormone which caused growth of the

sexual development and maturity are governed prin

mammary glands until Allen and Doisy

cipally by the ovaries.

Functional

guinea pigs (Steinach, 1912; Athias,

young or castrated

1915; Sand, 1918; Smelser, 1933),

and

mice

ovarian grafts in

(Gardner,

(Engle,

rats

stimulate

1935)

The atrophic changes which

growth.

1929),

mammary

follow

ovari

(1923)

pre

pared an active ovarian extract from the liquor folliculi and

developed

a

biological

method

assay

When Doisy,

standardization.

for

its

Veler: and Thayer

later crystallized a pure estrogen from human

(1930)

pregnancy urine, other workers,

in rapid succession,

ectomy in the monkey, described in an earlier part of

determined the chemical structure of the natural estro

this report, are equally striking.

gens as well as the androgens, progestogens, and some

The lengthy paper which Fellner published in

1913

reported the first successful effort to demonstrate the presence

in the ovaries of

a factor which causes growth

of the adrenocortical hormones.

All

these compounds

were found to belong to the general group of cyclo pentenophenanthrenes.

ESTROGENS

As

a result, renewed interest arose

ovarian

relation

its quantitative

and the

aspects.

Numerous

for

studying

experiments dem

degree

positive,

response

which

elicited varied from species to species. the effects

the the

In

Although type

and

estrogens

the majority

were limited rather sharply to an increase

in extent and arborization

The guinea pig

is the

treatment with large

additional treatment with a progestogen for the attain

uniformly

of the growth

rat and rabbit, by appropriate

on the mammary glands of

goat, cow, monkey, baboon, and human. results were

alone. Limited development of lobules

produced in some other species, such as the

amounts of estrogen. Most animals, however, require

the rat, mouse, cat, dog, opossum, guinea pig, rabbit,

the

from estrogens has been

effects of ovarian, and

onstrated the growth-promoting later synthetic, estrogens

in the mammo

possibilities

of the duct system. best-known

example of an

animal in which complete lobular development results

ment of full lobular growth.

In

the

human,

enlargement

nipples and proliferation occur after the

monly

synthetic estrogens 1941;

Scarff

Getzoff, Newman, castrated

the

administration

to males

and Smith,

1942; Pearlman

of

breasts

and

of the mammary ducts com—

(Dunn,

1942;

of natural or 1940;

Kahle,

Solomon,

Ogden,

and

and Pincus, 1943; Klein and

1944; Moore, Wattenberg,

and Rose, 1945),

females (Werner and Collier,

1933; Werner,

MAMMARY GLAND OF THE RHESUS MONKEY

development

Loeffel,

Freedman,

(MacBryde,

and

Castrodale, 1940; Lisser, 1940), pseudohermaphrodites 1944), children

(Bettinger,

(Woodrufi and Te Linde,

infants

1942), and newborn

(Speert, unpublished).

The histologic changes in the few mammary biopsies which have been performed before and after estro

marized in table 5, a positive growth

(Hoffmann,

operations Zuckerman,

1939)

1939;

Bishop,

Boycott,

were not sufficiently clear-cut or

consistent to permit conclusions as to the nature of the response.

The

effects

of estrogen on the mammary gland of

the monkey were first studied by Allen (1927, 1928a, who compared gross mounts of the breasts

1928b),

after treatment with control mounts from the same

Allen reported an increase in

animal.

gland, a dilatation multiplication

and branching

of the

alveoli.

the area of the

of the ducts, and a

In

these

experiments

relatively small amounts of estrogen were used (maxi mum average daily dose 50 r.u.) and the periods of were short

treatment

The

degree

trophic effects of estrogens,

Turner and Allen

monkey. found

in adequate dosage, in the

extensive

lobular

(1933),

development

for

example,

in

a

.male

after 65 days’ treatment with rather large amounts of estrone, and Gardner and Van Wagenen monkey

(1938)

obtained complete glandular

development

amounts, growth

Van Wagenen

of the mammary

animals, including

male

by Folley, Guthkelch,

and

that the

female

is more responsive to estrone

than is

(1939)

monkey’s breast

orderly

produced

development of the terminal knobs

or end. buds. Experiments Zuckerman

(1935)

glands of immature

have

suggested

that of the male.

The present observations on

the effects

of estrogens

of 100 r.u. daily, showed definite mammary

mary response

are sum

be expected,

animal’s ovaries were present. Thus, no. 693 showed to 50 r.u. of estradiol benzoate response

a positive

daily at the end of I month.

The

rate

of secretion of estrone

young adult rhesus (1940)

by

the

at about 200 International

one-half

roughly

represents

ovaries of

monkeys has been estimated by

found to be the minimal

Units daily.

of what

we have

effective dose for mammary

growth over a period of 50 days. It is to be expected, however, that a larger than physiologic amount would be required for the production of so prompt a response.

Our findings and Corner’s regarded as compatible

estimate

may therefore, be

and, to a degree,

mutually

supporting.

The experiments of Nelson and Van Wagenen

(1938)

(1936)

and of Gardner

are in general agreement

with our observations. The former reported distinct growth of ducts and lobules in 3 monkeys after 4 to 7 months’ treatment with 100 to 200 r.u. of estrogen daily for 20 and 63 days respectively. Folley, kelch, and Zuckerman (1939) claimed growth

Guth in the

glands of 4 out of 5 male monkeys which received estrone for 6 to 15 days, in amounts ranging from 500 to 50,000 r.u. per day, but a critical examination of

the

data

published

and

photographs

fails

to

definite evidence of mammary growth in these

animals.

Fifteen of the females were

As might

to estrogens.

smaller amounts of estrogen were effective when the

on I male and 24 females, large and small, which were treated with various preparations for periods ranging

The results of treatment

growth

in 50 days. The latter conditions of dosage and time appear to approach the minimum for detectable mam

reveal

from 12 days to 2% years.

major

of treatment.

during periods of treatment up to 45 days. One such animal (no. 140), which received Amniotin injections

on the monkey’s mammary gland include experiments

surgical castrates.

depended on two

and duration

Estrone or Amniotin, in amounts ranging from 25 to 100 rat units per day, was without effect in castrates

in

young males following treatment for 22 to 30 weeks with smaller doses of estrogen. Using intermediate

of response

factors, namely, dosage

Corner

ever, have clearly demonstrated the potent mammo

Amniotin (Squibb),

in oil, sometimes implanted in pellet form.

This

experiments by Allen and others, how

The

were administered subcutaneously, sometimes injected

for only a small part of the control gland was shown Subsequent

~.

by

estradiol, and estradiol benzoate. The test substances

for comparison with

the entire gland after treatment.

being

response

response

was responsive included estrone,

More

(maximum 24 days). over, the published illustrations were not convincing,

detectable

various natural estrogens to which the monkey’s breast

genic treatment of women who required plastic breast and

+, no

indicated by

We

have

found, however, that even

short a period as 2 weeks pronounced the ducts can be elicited

enough

(fig. 76,

pl.

1938), women with inadequate breast

1935; Guldberg,

35

if

in so

hyperplasia of

the estrogenic level is high

1;). Heroic experiments of this

MAMMARY GLAND OF THE RHESUS MONKEY

36

TABLE

5

MONKEYS TREATED WITH ESTROGENS

-

140 . . . 392 . . . 470 . . . 560 . . .

TREATMENT

..... .... ......... ......... .........

WEIGHT (GM.)

SEX

MONKEY

...... ...... ...... ......

... ... ...

... 626 . . . . . . . . . . . . . . . . . . . . . 660 . . . . . . . . . . . . . . . . . . . . . 687 . . . . . . . . . . . . . . . . . . . . . 693 . . . . . . . . . . . . . . . . . . . . . C15 . . . . . . . . . . . . . . . . . . . . . G20 . . . . . . . . . . . . . . . . . . . . .

F(c)’ F(c) F(c)

4120 4370 Immature

F

2580 6020

F(c) F(c)

4320 4120

F(c)

Estrogen

Amniotin Amniotin Estrone Estradiol Amniotin Stilbestrol Estradiol benzoate Stilbestrol Estradiol benzoate

F

4400

Estradiol

M F(c)

5970 3200

Estrone Estrone

benzoate

F

3470

Same

F

3940

F(c) F(c)

2890 3970

G27 . . . . . . . . . . . . . . . . . . . . . G29 . . . . . . . . . . . . . . . . . . . . .

F

G33 . . . . . . G34 . . . . . . G35 . . . . . . G37 . . . . . .

F(c) F(c) F(c)

...............

....... ....... ....... G38 . . . . . . . . . . . . .

........ ........ ........ ........

2670

F(c)

2180

F (c) F (c)

50,000 I.U./d. 25—100 r.u./d.

70 d.

+

0.1—1 mg./d. 50—150 r.u./d. 0.5—2 mg. /d. 50 r.u./d. 50 r.u./d. 2000 I.U./2 d.

Same

Same Same

Same

30 mo. 36 d. 11 m0. 17 mo. 29 mo.

Same Same

Same

2 mo. 10 mo. 23 mo. 15 mo.

Same Same

Same

3640 3100

Same Same

Same

33 d. 17 mo. 16 m0. 3 mo.

Same Same

Same Same Estradiol

Same Same 95 mg. subcutaneously

Estradiol

Five 3-mg. pellets/week 30,000 I.U./2 d.

Same

Same

Estradiol 1300

+

10 mo. 12 mo. 14 mo.

Same

1910

18 d.

Same Same

Same Same

F

5 mo. 8 m0. 19 mo. 12 d.

+ + + + + + + + + + + + + + + + + + + + + + + + + + +

Same

Same

+ + + +

106 d.

76 d.

Same Same

—

78 d.

Same

Same

—

30 d. 70 d.

Same

Same

G26 . . . . . . . . . . . . . . . . . . . . .

+

Same Same

3180 ....

2320

25 d. 30 d. 25 d.

5 mo. 85 d.

Same

F

—

Same Same

Same

—

45 d. 30 d.

Same

Same

F

+ +

3360

G32 . . . . . . . . . . . . . . . . . . . . .

G31 . . . . . . . . . . . . . . . . . . . . .

50 d. 32 d. 14 d.

Same

Same Same

Same Same

F(c)

100 r.u./d. 1000 I.U./d. 25 r.u./d.

8 mo. 11 mo. 14 mo.

Same Same G25 . . . . . . . . . . . . . . . . . . . . .

Duration

Same Same

Same Same G22 . . . . . . . . . . . . . . . . . . . . . G23 . . . . . . . . . . . . . . . . . . . . . G24 . . . . . . . . . . . . . . . . . . . . .

Dose

Two 3-mg. pellets/week 10,000 I.U./2 d.

Amniotin G21 . . . . . . . . . . . . . . . . . . . . .

MAMMARY RESPONSE

' F (c) signifiescastratedfemale. sort lend themselves poorly to an evaluation of the

found 1 month to be a reasonable period for testing

specific action of a hormone upon an end organ, for

mammotrophic

such large amounts of estrogen (113 mg. estradiol) induced profound metabolic disturbances in the test

substance

animal,

including

generalized

inhibition

(Hartman, Geschickter, and Speert,

1941).

of growth

We have

activity.

Moderate amounts of a test

may fail to produce their effects

within

a

shorter time.

The monkey’s

breast

responded qualitatively

same manner to the various estrogens,

in the

as well as to the

very large amounts of estrogen, to be

The mammary

described later, are excepted. to hormonal stimulation

of the normal growth extension,

consisted in an accentuation processes:

and

response

hyperplasia, dilata of

branching

the ducts, and

by

tion,

testo

thelial cells. In some cases lobular edema which separated tained

The lobules were main

the alveoli.

continued

was present

the loose connective tissue

and round cells infiltrated

estrogenic

treatment,

concomitant of the growth

for no evidence of glandular

process.

month’s treatment with moderate

amounts of estrogen (5o r.u. estradiol benzoate daily, ovaries intact) are shown in figures 72 to 75, plate 13,

to 30 months.

which

plete

corresponding

in the interlobular stroma, and the individual

even

decrease

the dilatation

alveoli (figs. 72, 73). Histologic

same specimens confirmed

of

sections

these changes (figs.

With large

I.U. Amniotin

doses of estrogen (10,000

5

trate in

days

that no increase

development was produced in

pre

interesting (figs. 81, 82, pl. 14). occurred in the area of the mammary

gland despite its high degree of internal development (figs. 81, 82). Whereas moderate amounts of estrogen growth in mammary area (Gardner and Van

cause

74, 75)

glandular

pubertal female in only 70 days (figs. 79, 80, pl. 14). Similar results were obtained in prepubertal cas a

in optical density of the gland,

growth of the lobules with

of the

mounts

LU.) of estradiol daily, com

mg. (50,000

85

the increase

a

show

of the whole

Photographs

With

a

typical biopsy specimens before and

represent

after treatment.

regression was observed

in animals under continuous treatment for periods up

is

1

of

thus in

state of complete development for an indefinite period,

It

a

mary gland apparently can be maintained

effects

the

together

more closely, mitotic figures grew scarce, and blood capillaries were less conspicuous. The monkey’s mam

growth of the lobules multiplication and dilata— tion of the alveoli. Secretory activity was not normal The

but

subsided, the alveoli becamepacked

edema

a

by

sterone and

changes produced

37

a

histological

by

certain

by

if

other hormones which exerted a trophic effect upon

it,

MAMMARY GLAND OF THE RHESUS MONKEY

Wagenen, 1938), large amounts of the hormone seem to exercise

an inhibitory

(Gardner,

1941:). lobular development occurred in an im

a

10 cells thick within month. This resulted in an initial narrowing of the duct lumina. Under suffi

ciently

intense

estrogenic

proceeded to the point

stimulation,

of virtual

stratification

occlusion

of the

lumina

months’ treatment.

As

the

dilate. nounced

lobules grew larger the ducts continued to

In

some

as to

(no. C15) which received 2000

I.U. of estrone every other day for 70 days. In contrast with the natural estrogens, two experiments in which

was injected with stilbestrol in oil daily for

places suggest

the cysts

dilatation when

was so pro

the ducts were

estrol used

(Engle and Crafts,

1939),

but the amounts

in our experiments may have been too small to

produce an effect upon the mammary gland. Christensen

tion subsided and the ducts reverted to narrow, one

pig that stilbestrol

layered structures, nestled inconspicuously

in causing growth of mammary tissue.

During this developmental

phase, microscopic examination revealed

a

10 months.

high degree

lobules, the interalveolar

being crowded with dilated blood capillaries.

spaces

Mitotic

figures were frequently seen among the cuboidal epi

and Noble

immediately

(1938) have

is

(1939)

Dodds,

and Felding and M¢ller

both observed in the guinea

only one-fifth as active as estrone

When no.

660,

after its failure to respond to stilbestrol,

was injected with estradiol benzoate in amounts in creasing from 50 to 150 r.u. per day, distinct evidence growth was found after 25 days’ treatment. of

among the

lobules of alveoli (figs. 77, 78, pl. 13). Lobular growth continued for varying periods, some

massive

the

mg.

per day, and no. 687 receiving 0.5 to mg. per day. The monkey’s uterus known to respond to stilb

ment, however, both the stratification and the dilata

of vascularity of

the

month,

no. 660 receiving increasing amounts from 0.1 to

Lawson,

as

in

Each animal

was tested.

viewed in histologic section. With continuing develop

as long

stilbestrol

had little or no effect on the monkey’s breast

is

2

(fig. 76). Beginning dilatation of the ducts and formation of lobules became evident after about

mature male monkey

1

to

1

duct

proliferating

stratification of the duct lining

6

elements, and the rapidly

cells produced

a

thelial

Moderate

on glandular extension

2

Many mitotic figures were found among all the epi

effect

it

a

week),

mammary growth increased in tempo and magnitude.

every other day and two 3-mg. pellets estrone

Because

of its capacity to induce growth

of the

mammary gland, the ovary has long been associated with cancer of this organ. Three decades ago Lathrop

MAMMARY GLAND OF THE RHESUS MONKEY

38

and Loch

found that castration resulted in a

(1916)

reduction

striking

in

the

incidence

of

mammary

carcinoma in a strain of mice highly Sixteen years elapsed,

the disease. successful

susceptible to however, before a

attempt was made to produce cancer of the

gland vwith estrogenic hormones (Lacas Males (which are normally resistant 1932).

were

malignancy

microscopically. (1939)

either

found,

Folley,

and Engle, Krakower,

sagne,

essentiality of the hereditary

disease)

strain of mice

and Haagensen (1943) to produce

mammary cancer in monkeys, even when older ani mals were used.

of a tumor-bearing

and Zuckerman

have likewise reported failure of estrogens

mammary to the

or

macroscopically

Guthkelch,

These experiments emphasize the (species) factor in car

cinogenesis. Spontaneous malignant

tumors are rare

developed mammary carcinoma after treatment with

in subhuman primates, and there has been no recorded

large amounts of estrogen.

case of cancer of the mammary gland in a monkey.

subsequently confirmed

These observations were

and extended by numerous

investigators (see review by Loeb, 1940). Mammary cancer has also been produced in rats by intensive estrogenic treatment (Geschickter,

In addition

for the development of mammary can

milk factor.

cer; namely, heredity and the so-called

Their

relative

importance

different species. predominantly (Allaben

varies

probably

work

Experimental

among

to date has been

on mice. Isolated clinical case reports

and Owen, 1939; Auchincloss

McCall,

sen, I940; Parsons and

in the breasts of 5 of our highly estrogenized monkeys. 10th week of treatment

At various periods after the

1939).

to hormonal influences, two other factors

are important

with the orderly development of the

Concurrently

mammae, benign metaplastic changes were observed

and Haagen

1941; Foote and Stew

small islets

of atypical pale epithelial cells appeared

in the glands, irregularly

of their pale staining

Because

among the normal

spaced

lobules and in the linings

mammary

groups of cells

of the

ducts.

characteristics, these

contrasted sharply with

the

normal

(fig. 83, pl. 14). The pale cells were cuboidal or polygonal and 2 or 3 times as large mammary epithelium

as the

normal

mammary

The faintly eosino

cells.

art, 1945) have suggested a possible carcinogenic action of estrogens on the human breast. Although the

cation, but at high power it was found to be finely

amounts of estrogen

granular,

required

for the production

of

philic cytoplasm appeared clear at low-power magnifi

malignant changes

nuclei, usually centrally located,

are proportionately

many times greater than the doses

also and contained prominent

ordinarily such

case

used

in the treatment of human patients,

reports, together with

tory studies,

the results of labora

have naturally brought into question the

complete safety

of prolonged

estrogenic therapy in

The monkeys which

underwent

long-term

treat

ment with very large amounts of estrogenic hormone interest.

Fourteen females

ranging in

weight from 2180 to 3970 gm., 10 of which were sur gical castrates, were treated by subcutaneous implan tation of two 3-mg. pellets

of estrone

weekly

and

injections of 10,000 I.U. of Amniotin in oil every other day.

Thirty-two mammary

specimens

were obtained,

by repeated biopsy and terminal autopsy, after periods

of treatment up to 30 months. The experiments were begun by Dr. Geschickter with a view to.deterrnining

the possibility of produc

ing mammary cancer in the rhesus monkey.

All

speci

mens were therefore studied in great detail, and patho

logical changes that

Pale epithelium was observed

were hypochromatic

nucleoli. in 4 of the IO castrated

monkeys (40 per cent), but in only I of the 4 animals with ovaries intact (25 per cent). Although this difference must be evaluated with consideration

for

the smallness of the numbers, evidence from another

women.

were of special

The large, round

sometimes vacuolated.

in the mammary glands of rodents

were carefully sought. Suffice it to say

no mammary tumors nor any change suggesting

source

attests

the possible importance of the absence

of the ovaries for the genesis of pale epithelium. Meta plastic changes resembling those which we have were produced in the mammary

observed

male and castrated amounts

female rats

treated

of estrogen, whereas such

glands of

with large

changes

rarely

occurred in the glands of intact females which were similarly treated

(Herold and Effkeman,

Pale epithelium breast,

1936).

was first described in the human

in the linings of mammary cysts, by Borst in

1904. Since then these atypical cells have been referred to in the literature as “blasse Zellen,” “idrosadenoid

epithelium,

’1 fl

“cosinophile

cellules claires,” “oxyphile

Epithelien,”

and “pale epithelium.” origin,

biologic

“helle Opinions

rosige

Epithelien,” Epithelien,"

concerning

significance, and clinical

their

importance

MAMMARY GLAND OF THE RHESUS MONKEY have been conflicting

Our findings support the view

(Speert, I942b). Pale cells are found in frequently mammary cysts in cases of chronic

mammary epithelium.

cystic mastitis as a result of metaplasia of normal

mammary carcinogenesis.

that pale epithelium

39

is not necessarily

with

associated

PROCESTOGENS

is

known of

there is no recorded experiment bined

Indeed,

on the primate breast.

its effects

showing

com

the

action of estrogen and progesterone

on the

No.

days.

The two hormones were administered female weighing

to monkey

with

613 was injected

daily for

pound

No.

18 days.

mg. of the com 20 mg.

620 received

mouth for 15 days. con usually takes siderably larger amount of anhydro-hydroxy-proges daily

terone

monkey’s mammary gland. no. 425, a castrated

ceiving

(ethinyl

produce

mouth than of progesterone

injection to

characteristic progestogenie effect.

When physiologic

3100 gm., in a

a

primed primate uterus have been well studied. Little

with anhydro

testosterone) after re injections of 100 r.u. of Amniotin daily for

hydroxy-progesterone

by

of progesterone on the estrogen

effects

(see

with

were also obtained in

females which were treated

5

The

gen.

propionate

It

organs which have been sensitized previously to estro

Positive mammary responses castrated

by

reproductive

by

on

effects

2

functional

8

and

testosterone

but not in animals which were treated

other hormones.

circumstance progesterone acts and produces its specific structural

with

which were treated below),

a

Significant amounts of progesterone are formed only

during pregnancy or, in the nonpregnant animal, during the luteal phase of the ovarian cycle. In either

or even

increased

moderately

manner designed to simulate a normal ovarian cycle.

amounts of progesterone are administered to castrated

For

animals,

Amniotin (100 r.u.) was injected daily. on the 8th day and continuing for 18 con

12 days

Beginning secutive

1 cc. of progestin

days,

also injected. Mammary

(70 gm. equiv.) was biopsies were performed be

fore and after treatment. Sections of the biopsy speci distinct growth of the mammary gland, the lobules and multiplication

of

progesterone,

effects

of

the hormone

They require, in addition or

preliminary

concurrent

to

treatment

with an estrogen. Thus, Fredrikson (1939) found the mammary glands of ovariectomized rabbits unre sponsive to progesterone alone, nor was any effect in the glands of castrated

produced

rats

so treated

When

15). These changes were which normally occur in

large enough amounts of the hormone were injected,

association with the menstrual cycle in intact animals.

however, characteristic development of the secondary

In explanation of this difference two factors may

sex

undergone

of no. 425,

gland

postcastration

the lobules or number

of alveoli.

would

atrophy,

more readily an increase

reveal

in size of

Second, by

of the amounts normally formed

the ovaries of the

parenchymal

growth

brought

interesting stromal changes were also ob—

in the mammary gland.

moderate increase of the blood

but more striking was the generalized change

cellular matrix gave

way to

a

in the character of the connective tissue. loose,

Its compact,

fibrillar

large quantities of interstitial

phenomenon

was observed also in

a

containing

to 20 mg., was injected

was

female monkeys2

which

doses

of

subcutaneously into

had beep

castrated

for

periods ranging from 37 days to years. Biopsies of the mammary gland were performed before and

stroma

fluid.

few

This

castrates

after treatment, duration 32 days,

curred

as shown

in each

(figs. 86, 87,

and multiplied

in table

case.

of which 6.

the

occurred in the number and dilatation vessels;

glands,

extended up to

Mammary

growth

oc

The lobules increased in size

15) as their constituent alveoli dilated

(figs. 88, 89, pl. 15).

The individual

alveolar cells grew larger and mitotic figures appeared among

them.

These

changes were greatest

2Monkey no. 673 was used, at different times, experiments, making experiments all together.

in 2

served

mammary

progesterone in oil, in daily

Crystalline from

pl.

gesterone,

to

combined treatment with estrogen and pro

A

by

In addition about

the

in rats (Selye, 1940; Reece and Bivens, 1942),

4

intact monkey.

including

1937).

mice (Mixner and Turner, 1942), and monkeys (Hart , man and Speert, 1941).

likely

that the injected hormones were somewhat in excess

organs,

effected

and Rausch,

Geschickter,

4

naturally

mammary

it

having

the

5

First,

mentioned.

be

(Astwood,

3

accentuated beyond those

is

the alveoli (figs. 84, 85,

pl.

mens revealed

with enlargement of

characteristic

the

usually fail to appear.

in the separate

MAMMARY GLAND OF THE RHESUS MONKEY

40

which

monkey

received the largest amount of pro

gesterone; namely, no. 673 after 32 days’

TABLE

6

treatment

of the animals receiving progesterone only, the con

—

nective tissue losing its denseness

MONKEYS TREATED WITH PROGESTERONE

TREATMENT

MONKEY

Sax

623 . . . . . .

CASTRATBD

50 days

4250

F (c)

37 days

F(e) F(c)

8% mos. 4 yrs.

4950 ....

F(c)

673 . . . . . . 673 . . . . .. 145C. . . .

wsmm (Gm)

Daily dose Days 5 mg. 20 mg.

7330

growth

effects

MAM may na smnsx

27

talline progesterone, in adequate dosage, inducing its mammotrophic have been castrated

effects

and

is capable of

in monkeys which without

as long as 4 years,

liminary priming with estrogen. As in castrated

+ + + +

32 19

Similar

and cellularity

becoming loose and edematous (figs. 88, 89). These experiments clearly demonstrate that crys

32

10 mg. 20 mg.

with 20 mg. of the hormone daily. pronounced

the other 3 experiments. The stromal changes men tioned in an earlier paragraph also occurred in each

however, much

but less

were observed in each of

which

required

estrone

was

Turner,

1942),

injected the

6 times

approximately

for

progesterone

alveolar

pre mice,

growth

as

as

when

(Mixner and

simultaneously

amounts of progesterone used

in

the present experiments were well beyond the physio

logic range of the monkey.

Gomnonornms The administration

of

animals.

most laboratory

gonadotrophic

of the mammary

results in development

Extracts

hormones

and to correlate the resulting mammary effects

glands in

the changes which

of pituitaries,

of

human pregnancy urine and blood, and of pregnant mare serum produce varying

of mammary

degrees

in the rat, mouse, rabbit, and other species.

growth

Differences

exist as to the presence

of opinion

of

with

occurred in the ovaries.

Biopsies of the mammary

gland

were performed

before and after treatment of 3 nonovulating, amen orrheic adult females with various gonadotrophic These experiments were included

preparations.

in a

previous report by Hartman

(see section on “Mode

(1942). no. 699 received subcutaneous injections of " a mixture of 1 unit of FSH (Iensen) and 10 units

tain extracts

of Follutein (Squibb)

mammary 7 which

pituitary

the

of action of hormones”). Cer of this gland are capable of stimulating extracts

contain

animals.

in castrated

development

purified

ever,

in

hormones

mammotrophic

specific

of pituitary,

gonadotrophic

How

blood, or urine

hormones

to

the

ex

clusion of others require the ovaries for the mediation of their effects

on the mammary

glands.

They

are

ineffectual in castrates. mouse, rabbit, dog, cat, horse,

rat,

gonadotrophic

next

19

a

daily for

treatment

days

hormones

provides

as

and ewe to

a ready explana

16 days.

consisted of

(Upjohn),‘ beginning with

Gonadogen

For the

injections

of

10 units daily,

decreasing to 3 units daily, and then increasing to 50 units daily, a total of 141 units. Although this treat ment

produced

no palpable

uterine bleeding occurred

The sensitivity of the ovaries of animals such the

Monkey

FSH-Follutein indication

injections.

effect

of ovarian activity.

mary gland

revealed

on

the ovaries,

during the course of the This may be taken as an Biopsies of the mam

a poorly

developed system

of

tion of the impbrtance of the gonads in this reaction.

lobules consisting of but a few end buds at the be—

Follicular development and luteinization,

ginning of treatment (fig.

sult from gonadotrophic

stimulation,

of estrogen and progesterone.

which

re

produce sources

These, in turn, cause

growth of the mammae. Species

recalcitrant,

of their ovaries

The rhesus monkey

especially

to

attempts

to

is notoriously cause

it

to

ovulate (Hartman, 1938, 1942). It was therefore of interest to examine the mammary glands of monkeys which

were treated

90, pl. 16). After treatment end buds were somewhat increased in number

and had undergone slight branching and pronounced dilatation

differ greatly in the response

to gonadotrophins.

the

in an effort to induce ovulation,

(fig. 9!, pl. 16). On the whole, however, was slight after 35 days’ treat

mammary stimulation

ment with these gonadotrophins. Monkey and

no. 673 was injected with FSH, Follutein, intermittently over a period of 4

Gonadogen

3 Extract of human pregnancy urine. 4 Extract of pregnant mare serum.

MAMMARY GLAND OF THE RHESUS MONKEY months.

FSH

began with 5 units of

Treatment

and

41

Five units of FSH and of Follutein were injected daily for 22 days.

when treatment was begun.

50 units

50 units

of

of Follutein daily for 22 days. After a lapse days 5 units of Gonadogen were injected daily

No apparent stimulation of the ovaries resulted,

11 days, then 10 units daily for 3 days, and finally

as could

for

30 units intravenously,

a total of 115 units in 16 days.

determined

be

remained

by

6

the uterus failed

unaffected;

so far

the sex skin

palpation;

to increase

One month later another course of injections of FSH

in size; and no bleeding occurred during or following

and Follutein,

treatment.

was indicated by uterine bleeding during the

first

course of treatment

with

and by

Gonadogen

swelling of the sex skin and bleeding from the uterus after the second

of injections

series

FSH

with

and

Follutein; but again there was no palpable change in the condition

of the ovaries. Good mammary growth the several

occurred during

courses

specimen at the beginning

biopsy trophin

of treatment.

A

of the gonado

injections showed the mammary gland to be atrophic, as was consistent with the amen

distinctly

orrheic condition

Only narrow

of the animal.

and a few shrunken

ducts

lobules were present (fig. 92,

pl. 16). Following treatment the gland was moderately well developed, numerous lobules of alveoli having

The occurrence of mammary growth

mary glands.

could be correlated with other evidence of ovarian stimulation.

Since our observations were limited

animals, however, the role of the gonadotrophins

key

to

Ovarian activity in the rhesus mon

merely suggested.

subject tO many

vagaries.

Experiments

based

hormones must there

on the action of gonadotrophic

fore be interpreted with reservations. Despite the fact that the animals were nonovulating

of the ducts had also occurred

16). no. 667 had been amenorrheic for 79 days

Monkey

change in them, can cause development of the mam

ovarian activity were not caused

pl.

(fig. 93,

(Hart

man, 1938, 1942).i The present experiments indicate that such ovaries, even in the absence Of palpable

moderate

end buds.

amenor

the ovaries of nonovulating,

rheic adult monkeys under certain conditions

one cannot be certain that the

sprouted from the proliferating degree of dilatation

A

pregnancy urine and pregnant mare serum are capable of stimulating

awakening

of the

dormant by

lation

is

of Gonadogen injections was given 2 months later, consisting of 10 units daily for 5 days. Ovarian stimu

biopsies revealed no change

Mammary

in the gland. The gonadotrophic hormones obtained from human

their stimulation

and amenorrheic, results of

Observed

spontaneous re

gonads rather than

by

second series

by

A

is

former and 10 units of

3

1 unit of the

the latter daily, was given for 16 days.

the test hormones.

and Folley,

pigs (Bottomley

responsible for the normal proliferation

propionate, caused

extension

of the

of mammary

duct system,

and de

by

velopment of lobules Of alveoli, these effects achieved experimentally

The mammotrophic sex

in

hormones, several

pionate,

duced duct growth Gallagher, Astwood, 1939;

Testosterone,

androstenediol,

trated and intact

Reece

1936;

be

action of the androgens, or male

for example, has been

species.

can

other hormones as well.

and

demonstrated

testosterone

androstenedione

of both

Selye,

Geschickter, and Mixner,

and

1939;

1937;

Laqueur

Noble,

and Fluh

mann, 1942; Laqueur, 1943). Testosterone propionate, and As-trans-androstenediol 17-methyl testosterone,

5

stimulated growth

of the mammary

with methyl

The

testosterone

(McCullagh and

1941).

effects

of androgens on the monkey’s breast Folley, Guthkelch,

and Zucker

Van Wagenen and Folley (1939). man (1939) and The former authors treated male animals with testo

1936;

Rausch,

therapy

Rossmiller,

pro

(Nelson

and

in sterile

have been studied

McEuen, and Collip,

sexes

udder and teat growth

heifers (Reece, 1943). In the human, gynecomastia resulted in several male patients who underwent

pro

and alveolar development in cas rats

compounds

ducts in guinea

by

epithelium,

1938); and the first of

together with diethylstilbestrol

these

di

has been established beyond doubt that

estrogens and progestogens are the hormones primarily

by

Although

it

ANDROGENs

sterone

propionate and reported dilatation of the ducts

and formation

of alveoli but no significant

increase

in the area of the glands. The latter authors adminis tered

various

androgens

to castrated

preadolescent

females and compared the mammary gland after treat ment with the control

They

too

gland

observed dilatation

removed

beforehand.

of the ducts, without

MAMMARY GLAND OF THE RHESUS MONKEY but denied the capacity of

to produce alveolar develop

propionate

testosterone

heaping of

resembling intraductal papillomas, in

the epithelium,

with this hormone. The present experiments comprise three groups of

an occasional animal treated 10 animals

monkeys:

treated with

(testosterone, testosterone

androgens methyl

propionate,

connective

tissue

described in the pro

gesterone-treated animals were also present in a few

ment unless alveoli were already present in the gland. Both groups called attention to irregular

interlobular

among this group (figs. 96, 97). A castrated male (no. M8) and a castrated

female

(no. 463) were injected for 2 weeks with 5 and 10 mg. of testosterone daily, respectively. Mammary growth in both cases but to a lesser

extent than

alone

resulted from treatment with testosterone

propionate.

testo

In the male, moderate dilatation

and androstenediol) (table 7); 3 castrated females treated concurrently with an estrogen and an

sterone,

occurred

of the ducts was

observed, as well as lobular development (figs. 98, 99, pl.

extension or arborization,

TABLE

17).

7

42

MONKEYS TREATED WITH ANDROGENS

TREATMENT WEIGHT (0)1.)

MAMMARY RESPONSE

Androgen

Dose

Days

50 mg./d. ......................

28

.

SEx

l

MONKEY

F(c)

10 mg./d. . ..... .. .. ...... ...

propionate

(c)

M (c) F(c) F(c)

.

No treatment

F(c)

5540 4590

Testosterone

. .. 3350

Testosterone

6020

Androstenediol . . . . . . . . . Methyl testosterone

Testosterone

.

.

propionate

propionate

+

10 20 25

+ +

— —

35

10 mg. /d. mg./d. (by mouth) mg./d. 2% mg./2 d. 10—20mg./d. (by mouth)

Atrophy

+ + +

13 20 15 33

— —

5

21/2 mg. every other day for 33 days,

Details of the experiments are

castrates.

shown in the tables.

A

positive growth

response

response

—.

group receiving androgens alone (table 7), females were treated subcutaneous injection of by

testosterone

propionate, in amounts ranging from 10

treatment,

distinct

enlargement

of the

a

intact. As

Three

result of

lobules and

of the alveoli occurred in each case (figs.

androgenic

upon withdrawal

effect

development

treatment

mouth daily in

which

was quickly

of the hormone.

female

resulted reversible

In no.

591 and

no. 427 mammary biopsies 28 and 35 days, respectively, after cessation of treatment revealed gross atrophy of the

lobules with cellular

infiltration

of the

stroma,

collapse of the alveoli, and shrinkage of the cells (figs. 17). These changes probably occurred after the 2d week of hormonal withdrawal,

100, 101,

rapidly

94—97,

pl.

dilatation

2

to 50 mg. daily, for periods from 16 to 31 days.

of the animals were castrates,

The lobulo-alveolar from

the

week, were each

pl.

+, no

by

indicated

a

without

is

(table 9). Mammary and after treatment.

for

by

10 to 20 mg.

biopsies were performed before

2

4

Androstenediol,

and methyl testosterone,

by

castrated females treated (table 8); and with an androgen after priming with an estrogen

5

31

Primed with Amniotin (100r.u./d.) for days beforetestosteroneinjectionswere begun;i.e.. beforecontrol biopsy. wasbegun;i.e..beforecontrolbiopsy. Primed with Amniotin (increasingfrom 25to 100r.u./d.) for 42daysbeforetreatmentwith methyltestosterone

androgen

In

30 12

+

. . .

No treatment

. . .

Testosterone Testosterone

.

4860 4110

propionate

.

Testosterone

.

3800

5 2

. . .

.

.

F(c)

20 mg. /d. ...... .......... ..... 20 mg. /d. ............... .... . 15 mg./d.

propionate

No treatment

.

......

. . .

.

.

6261'. . . 1' "‘

......

.. . ...... .. .... .. .... ... .

.

.

.

.

463' . . . . . . . . . . . . . . . . 591 . . . . . . . . . . . . . . . . . M8 . . . . . . . . . . . . . . . . 472 . . . . . . . . . . . . . . .

Testosterone

.

.

.

.

.

.

620 . . . . . . . . . . . . . . . . . . . . . . . 427 . . . . . . . . . . . . . . . . . . . .

5040

F

........

F(c)

F

. .

..........

.

. . . . . . .

692 . .

........ . . .... . . .

.

681

+ Atrophy

16

7

propionate

No treatment

.

Testosterone

.

4590

F

. ...

. . .

.

.

591 . . . . . . . . . . . . . . .

16). N0 dilatation of the ducts, however, and little evidence of secretory activity were to be

for they were not found in biopsy specimens obtained

found.

Stromal changes similar to the edema

after treatment was stopped.

of the

from no. 692 and no. 681, 10 and 12 days respectively

MAMMARY GLAND OF THE RHESUS MONKEY Various combinations of an estrogen and an andro gen were administered

subcutaneous injection

by

ester abolished the vaginal response

rat

to

females for short periods, 10 to 21 days

3 castrated

(table 8). A positive mammary response was obtained each instance. In no. 256 and no. 603 the amount

cause

inadequate,

mammary

detectable

in

development.

(Courrier and Cohen-Solal,

(Shorr,

androgens are distinctly

itself, to

of the sex skin

It

confirm

seems

the

TABLE

(Hartman,

When

these

human

1938).

a reddening

causes

1937).

Present findings

action of androgens

mammotrophic

the

monkey.

and

In other estrogenic. In the

monkey, for instance, testosterone

reasonable, therefore, to attribute the observed response

to estrogen in the 1937)

and Stimmel,

Papanicolaou,

respects

in

of estrogen was probably

43

are

in

in con

administered

8

MONKEYS TREATED CONCURRENTLY WITH ESTROGENSAND ANDROGENS

TREATMENT MONKEY

WEIGHT (GM.)

SEX

Estrogen

256' .. . 597. . . .

F(c) F(c)

5270 3520

Amniotin Estrone

603. . . .

F(c)

4400

Amniotin

Estradiol

Androgen

Daily dose

propionate

Daily dose

Days

MAMMARY RESPONSE

+

10

50 r.u.

Testosterone

lK-mg. pellet

Methyl testosterone

25 mg. Six 3-mg. pellets

18

1 mg. 25 r.u.

Methyl testosterone

10 mg.

21

+

' Primed with Amniotin (100r.u./d.) for 8 days beforecombinedtreatmentwas begun;i.e.. beforecontrol biopsy. TABLE

9

MONKEYS TREATED SEQUENTIALLY WITH EsTROGEN AND ANDROGENs

TREATMENT MONKEY

WEIGHT (cm)

SEX

Daily dose

Hormones

F(c)

4510

Amniotin Amniotin

100 r.u. 25 r.u.

Testosterone 585 . . . . . . . . . . . . . . . . . . . . . . . .

F(c)

4350

Amniotin

50 mg. 50 r.u.

584 . . . . . . . . . . . . . . . . . . . . . . . .

F(c)

5850

Amniotin

613 . . . . . . . . . . . . . . . . . . . . . . . .

F(c)

4380

Testosterone dipropionate Amniotin Methyl testosterone

Testosterone

either to the androgen alone or to a synergistic action

junction

of androgen and estrogen.

quentially,

When gens

castrated

with andro with Amniotin, a positive

females were treated

after being primed

was obtained in 3 out of 4 experi (table 9). Methyl testosterone, by mouth, was ineffective. But in the 3 other animals distinct mam

growth

response

ments

mary

growth

resulted

from

the

sequential

first of Amniotin, and then of testosterone

action,

or one of

In

some

i

18 5 17 19

25—100r.u. 10 mg. (by mouth)

with

estrogens,

either concurrently

102, 104,

or se

the contrary,

with

a

gland.

po

resultant Monkey

a good example of this synergism.

At the beginning of treatment of this castrated

On

that estrogenic priming

of androgens,

synergistic action on the mammary no. 602 furnished

—

9

no antagonism appears. the effect

+

15 10

the

mammary

gland

female was completely atrophic (figs.

17). Amniotin (100 r.u. daily) was in following which 25 r.u. of Amniotin

jected for 12 days,

its esters.

estrogens.

12

100 r.u. 5 mg.

our observations suggest tentiates

Days

10 mg.

propionate

pl.

602 . . . . . . . . . . . . . . . . . . . . . . . .

MAMMARY RESPONSE

respects

androgens

For example,

are

testosterone

antagonistic

to

and its propionic

and 50 mg. of testosterone the next 15 days. Mammary

were injected daily for biopsy at the conclusion

of this treatment

showed

remarkable

a

degree

of

their animals only once or twice

A

a

MAMMARY GLAND OF THE RHESUS MONKEY

44

week rather than

lobular development, with dilatation of the ducts and

every

alveoli and many mitotic figures (figs. 103, 105, pl. 17). This rapid developmental change was far greater than

countered in the mammary gland during the first few days after the cessation

of treatment with

that experienced by no. 591 in response to 50 mg. of testosterone propionate daily for 16 days without

trophic hormone.

suggested,

observed secretion may have resulted, at least in part,

estrogen.

from

tion, resulting in microscopic papillomas, occurred in

received androgens

concluded that epi

is

2

it

animals 17). From these thelial heaping can be induced

(figs. 105, 106, by

which

group

estrogen, and in

of the monkeys treated

minority

propionate

testosterone

by by

occurred also in

Guthkelch,

Folley,

Van Wagenen and (1939). Its significance, especially in relation

and Zuckerman

(1939)

and

mastopathies in women, and the possi

to proliferative

bility of producing

or preventing

it

Folley

or its

testosterone

or intact monkey. This type of hyperplasia

castrated

a

a

propionate, either with or without

with

pl.

the mammary glands of these same two (no. 602 and no. 591) but in none of the others among the entire

with other hor

are

a

is

It

substances

clear secretion

and dilated ducts in sections of the breasts of monkeys

1941; Fraser and others, 1941).

1939; Werner,

compounds

origin, since they are contained in essentially the same titers in

of ovariectomized

urine

the

women

others,

and

(Hamblen Furuhjelm, 1940). The commingling of “mascu line” and “feminine” hormones in the urine has been referred to Frank (1940) as “chemical hermaphro Andric and gynic factors

ditism."

are not necessarily

opposite in character, but rather covariant, forming what

Draper

has

(1944)

When

drogyny.” of estrogens 1939).

called

in the

urine

Zondek (1934)

the various effects which testosterone

of the epithelial

of

leads to dilation

which

cells,

the

secre

in turn

the ducts.” These authors injected

that endog—

capable

of the large quanti

which

are

normally

Considering

of producing

ex

further

and its related in female ani

mals, such as enlargement of the vagina and uterus (Korenchevsky

and Hall,

and progestational

1937)

changes in the endometrium,

it

of

are

becomes

apparent

that the term “male sex hormones,” as applied to these compounds,

is a

tory condition

on

propionate)

testosterone

a

with

(particularly

compounds

an

and Towne,

has even suggested

of estrogenic hormone

of

injected

rise occurs in the level

(Nathanson

We must therefore disagree with the statement of Van Wagenen and Folley that “in the rhesus monkey

ties

“mosaic

propionate

testosterone

creted in the urine of the stallion.

mammary gland consists of the induction

normal

Hirschman,

1939;

not dilated nor did they contain any visible secretion.

of androgens

and

1939;

enous androgens are the source

effect

These

presumed to be of adrenal cortical

are

with androgens (fig. 105). These phenomena, however, were inconstant. More often the ducts were

most consistent and striking

a

is

and others, 1937; Callow and Callow,

men (Gallagher

treated

the

in significant

excreted

quantities in the urine of normal women as well as

into human female castrates,

few instances we observed

a

In

a

mones, remain to be clarified.

withdrawals.

of hormonal

succession

Androgenic

en

mammo—

is

prolifera

commonly

therefore, that the

a

epithelial

a

and intra-alveolar

reaction

secretory

by

Intraductal

day.

misnomer.

DESOXYCORTICOSTERONE

shown

that

salt

desoxycorti

and

water.

is

The most important

physiologic action of this compound of

A

widely used clinically in the treat

ment of adrenal insufficiency. metabolism

is

member of the last group

which

is

well known costerone,

and the corticosteroids.

estrogens

Desoxycorticosterone (Salmon, 1939).

and

monkey,

simulating

it

it

(Speert,

chicken,

exerts

an estrogenic

In

castrated

monkeys

increases

the

of the sex skin, and produces bleeding from the uterus

species

pig,

acetate

have

Experiments

the mouse, rat, rabbit,

guinea

in

vaginal desquamation, causes reddening and swelling

of laboratory animals, including cat,

actions, progesterone

on the body’s

secondary sex organs

affects

its

effect on the vaginal smear of postmenopausal women

the

also

in certain of

others, and androgens in still others.

it

Close chemical relation exists between the sex hor mones, the 17-ketosteroids,

1940a).

After estrogenic priming in this

can also bring about progestational changes

in the endometrium

and inhibit

estrogen-withdrawal

MAMMARY GLAND OF THE RHESUS MONKEY bleeding (Engle,

1941; Zuckerman,

Mammary

1941).

growth has been produced in male mice by treatment

with

mg. of desoxycorticosterone

0.5

acetate

every

observed in

specimen of

biopsy

the

45

no. 592 after

similar treatment for 13 days. Another biopsy 11 days later, however, revealed distinct glandular growth,

other day (Van Heuverswyn, Folley, and Gardner, 1939); and enlargement and tenderness of the breasts

Thus,

were observed in a patient with Addison’s disease who

mary stimulation, even over as short

received 15 to 20 mg. of this compound daily. When treatment was stopped, these symptoms subsided and

ment as 13 days, but more time was needed for the manifestation of its effect. The latent period required mammary

treatment

showed no mammary

response

of desoxycorticosterone

Daily dose

tion than

more important

the total quantity of test substance

Desoxycorticosterone the adrenals.

703. . 592. .

F(c)

6 wks. 8 wks.

5070

620. .

F(c)

6 wks.

5520

F(e)

4880

a

is

MAM~ _, MARY RE Days SPONSE

was greater than that given no. 592 in Obviously, the intensity of hormonal stimula

is

TREATMENT Sax

5-mg. daily dose

this period 24 days.

CAS\VEIGHT TRATED (01m)

no. 620

10 mg. 10 mg. No treatment 5 mg.

24 13

+

11

+

—

—

30

acetate

for mammary intimately

development injected.

associated

with

has been isolated from adrenal cortical

(Reichstein and von Euw, 1938). Dorfman and others (1944) have extracted from the urine of cas tissue

trated male and female monkeys protects adrenalectomized

rats.

a

10

MONKEYS TREATED WITH DESOXYCORTICOSTERONE ACETATE

MosKEY

to

to

response

Monkey

after 30 days’ treat ment, even though the total amount received during

It

TABLE

interim.

period of treat

for

gland

variable.

a

a

the monkey’s

hormonal

is

1943).

The present experiments include observations on castrated female monkeys which were injected with

the

daily dose of 10 mg. was adequate for mam

is

3

by

the breasts returned to normal (Lawrence,

though no treatment was given during

material

which

This material could

daily for

acetate

but was restored in one animal

monkeys,

periods up to 30 days. Mammary biopsies were made before and after treatment. Details are shown in

injection of desoxycorticosterone acetate.

table 10. Excellent

hormones also.

pl.

daily dose (figs. 107—110, and

appeared in their walls. found

nanediol, an end product of progesterone (Hoffman,

and

Little

any

of the duct epi

striking

mammary

figures

increase was connective

development

was

for example, results in the excretion of preg

Kazmin, and Browne,

1943).

Such

almost identical effects not surprising

when

on the mammary one

progester

considers

their

gland, are chemical

structures

(.ZHZOH C=O c";

CH

(ZH3

//

//

ESTRONE

in

and desoxycorticosterone to produce

one, testosterone,

CH3

HO

similarities

their behavior, and the capacity of estrone,

ll 0

tissue.

Proliferation

occurred,

also

their patency

mitotic

in the thickness of the periductal

if

thelium

it

acetate,

numerous

a

re-established,

with the sex of desoxycorticosterone links The injection of desoxycorticosterone

18). The atrophic

lobules enlarged, the alveoli multiplied, was

lism

treatment with a

in no. 703 as a result of 24 days’ 10-mg.

was obtained

response

the

The metabo

I

mammary

by

not be recovered from the urine of adrenalectomized 5 to IO mg. of desoxycorticosterone

TESTOSTERONE

PROGESTERONE

DESOXYCORTICOSTERONE

MAMMARY GLAND OF THE RHESUS MONKEY

46

Each contains a steroid nucleus and, with the excep tion of estrone,

and accessory by listing

derived from progesterone by the mere substitution of

vaginal epithelium.

a hydroxyl group at C21.

differences

in

To

chemical

be sure, even such minor

structure

in altered

result

physiologic potency, so that larger amounts of desoxy than of progesterone are required

corticosterone

to

actions in experi

produce certain progesterone-like

mental animals (Robson, 1939; Van Heuverswyn

and

1943)

Clark and Selye

organs.

sex

a-B-unsaturated ketone group at is all. Desoxycorticosterone can be common to C3—C4 the

have stressed

the nonspecificity

49 of them that can cause

Mammary

response

thetic, would

seem,

to

(1942,

of the steroids proliferation

natural or syn

hormones,

then, to be a function

potency of the test substance,

dose, duration

of the of treat

ment, and the degree of uptake and utilization hormone by the gland.

of

of the

The possible importance of

the last factor should not be overlooked, for occasional

others, 1939). Still, in adequate dosage each member of an imposing list of steroid compounds has been

cases have been

found capable of stimulating growth of the secondary

Wilson,

reported of girls with infantile geni

talia and enormous, growing breasts

(Kurzrok and

1940).

MODE OF ACTION OF HORMONES ACTION ON THE GLAND

A

theory of mammary

which

development

was

proposed in 1931 by Turner and Frank, namely that the mammary ducts develop in response to ovarian the lobules of alveoli in response

estrogens,

to

the

added stimulus of progestin, served for about a decade as the

of mammary

basis

developmental

physiology.

observations, however, have necessitated

More recent

reconsideration

of the mode of action of hormones

upon the mammary gland and a modification

The demonstration Brooks, Others

of the

simple scheme.

original

and Seidenstein

Salisbury,

(1936), and by

that mammary growth resulted from the injec

tion of aqueous alkaline trated virgin Catchpole

that growth

by Lyons

well

as

suggested

the

and

as secretion

occurred in the glands of ovariectomized bits following the injection

into cas

extracts

pituitary

rabbits, and the finding

(1933)

ysectomized mice which

virgin

rab

of lactogenic hormone,

importance of the pituitary

for mam

mary growth through some mechanism other than its gonadotrophic action. Evidence of the indispensability Of the pituitary was furnished by several

described the failure of estrogens

reports which

to stimulate

mam

rats (Selye, Col Turner, and Hill,

1937).

Although

were treated with various

of the pituitary, insuffi

a small fragment

estrogens,

cient to maintain the gonads or adrenal cortex, sufficed to allow

of the mammary

growth

the administration

glands following

of estrogenic hormones.

guinea pig, too, estrogens although

the

nipple

unaffected by the absence

response

(Lyons and

and Turner, 1936). Further on rabbits, cats, and ground squirrels

1936; Gomez

Pencharz,

experiments

extended tO these species

the observation that estro

gen, even when administered together with progestin, was ineffectual in stimulating animals.

hypophysectomized

mammary Lacassagne

growth and

ysectomized mice of a susceptible strain. Other steroid hormones of known mammotrophic activity

Collip,

such as testosterone 1937),

testosterone

(McEuen,

propionate

Leonard

(Chamorro,

either alone or in combination

with

Reece

Tobin,

and Leonard,

and Collip, 1936; In animals with intact pi

1936; Selye

1941).

tuitaries, on the other hand, or animals which received pituitary

implants

simultaneously

or injections of pituitary

with

estrogens,

the

extracts

latter provoked

their characteristic extension of the mammary system.

duct

Similar findings were described in male mice

and Reece,

and

Selye,

(Noble,

and desoxycorticosterone acetate

1936; Nelson and

in

Cha

morro (1939) have also described the failure of estro genic hormones to induce mammary cancer in hypoph

lip, and Thomson,

Reece,

the

appeared to be

of this gland

mary growth in hypophysectomized 1935a;

In

induced little if any mam

mary growth after removal of the hypophysis (Vargas, 1943),

(1930), by Asdell,

Corner

by

Hill,

(Gomez, Turner, Gardner, and

no mammary response occurred in completely hypoph

1942; Reece and Leonard,

1939; 1942), 1940a),

estrogen,

like

wise have been found to exert no effect on the mam mary glands of hypophysectomized although the

growth

rats

and mice,

of the nipples and retardation

regression of the secondary sexual

of

organs were

observed. Evidence

has

been

presented that

mammary

de

I

MAMMARY GLAND OF THE RHESUS MONKEY can be produced

velopment

in hypophysectomized

pituitary

of pituitaries

Turner,

male guinea pigs by the implantation

from animals of

the same or other species which have

47

II”;

(“mammogen

ectomized

Mixner,

Lewis,

and

and a method for its assay on ovari

1940),

mice has been

virgin

described (Mixner

been treated

previously

with estrogen, whereas the hypophyses of untreated donors are relatively in effectual (Gomez, Turner, and Reece, 1937; Gomez

and Turner, 1941). Recent analyses have shown this factor to be protein in natute, in common with other

and Turner,

1937).

tinct from the lactogenic, thyrotrophic,

Gomez

Reece and Leonard

that the pituitaries

later found

(1942)

and

(1939)

of

untreated as well as estrogen-treated rats of both sexes exerted a mammotrophic

on castrated

effect

and on

crease

in

pituitary

was unable to demonstrate an in

(1939)

the

activity

mammotrophic

with

after pretreatment

of

estrone,

rat

the

although

and Turner (1938b) had observed such an augmentation in the rabbit after injection of anol as Gomez

The latter authors con

well as steroidal estrogens. cluded that estrogens mammary

gland

produce their effect mediation

the

through

upon the of

the

1942).

Before these “mammogenic

The anterior

pituitaries

of pregnant

cattle were

found to be a good source of this pituitary “mammo gen”; the glands of nonpregnant

cattle,

on the other

their content of lactogenic

hand, despite

little

if any “mammogen,”

hormone,

according

to

Gomez and Turner (1938a). These investigators also of two distinct “mammo postulated the existence genic factors” in the anterior pituitary: a “duct growth factor,” formed as a result of estrogenic stimulation, and a “lobule-alveolar

factor," a product of

growth

progestogenic activity.

tions must be answered.

of the pituitaries,

pregnant

or estrogen-treated animals,

have contained

small amounts of estrogenic

especially of might

legitimate objec

Despite the negative results

of one assay for estrogen, extracts

its highest concen

other

factors, could

pituitary

induce

a

mammary

of sufficient degree to be considered positive

response

by the “mammogen”

ysectomized

male

Turner, and

Reece

guinea

pigs

(1937)

the

Employing the McGinty intra-uterine Trentin, Mixner, Lewis, and Turner

obtained negative assays for progesterone with

(1941)

amounts of fresh pregnant cattle pituitary which were capable of stimulating growth of mammary lobules in female mice; negative assays for progesterone

were likewise

obtained with lipid

It was distinguished from estrogen

adrenals might

male

The uterine

hormone origin, and

mammary

and Turner, 1942). Evidence has also been of the second

rat

(Lewis,

Gomez,

adduced for the existence

“mammogenic

factor” in the anterior

Nelson

extracts

male mouse.

to progesterone might have been

of

if any adrenotrophic

Several steroids of adrenal androgens, progesterone,

estrogens,

(1941b)

of

Also, stimulation of the

occurred

have

glands

pituitary

in the

by a sufficient concentration

was present.

including

(Lewis, Turner, and Gomez, 1939). Mammary gland development with the duct growth factor, also known and in the hypophysectomized

response

however,

desoxycorticosterone,

tivity.

I,” was later described in the castrate

duct growth

stimulated

mice after the daily injection of this factor for 6 days

as “mammogen

of

implants.

technique,

estrogen in the test material.

occurs in immature

Gomez,

pituitaries

negligible amounts of estrogen were transferred with

in not being isoelectrically precipitated from alcohol.

which

which

estrogen-treated donors, it seems likely that more than

inhibited,

mary development

in

implanted

anterior pituitary in being soluble in lipid solvents and by being heat labile

of the

nipples as well as the glands occurred in the hypoph

which

(Lewis and Turner, 1939). An assay method was developed, based on the mam

Tur

of Lewis,

assay technique

tration in the cow’s pituitary at about the 150th day of pregnancy and differed from other hormones of the

to oxidation

with

hormone which, either alone or in combination

castrated

The duct growth factor reached

and subject

factors” can be accepted

ner, and Gomez.ls Since extensive development

pituitary.

contained

and gonado and Turner,

(Mixner, Bergman,

hormones

trophic

as new and distinct entities, several

sexually immature females. Nelson

hormones of the anterior pituitary, but probably dis

have

has

mammotrophic

induced

growth

ac

of the

gonadectomized-hypophysec

5In a more recent report Trentin, Lewis, Bergman, and Turner (1943) have admitted the possibility of estrogen contamination in the lipid pituitary extracts. Using improved extraction procedures these authors now believe “mammogen I" to be protein rather than lipid in nature. In another paper Mixner and Turner (1943) reported that pituitary l“mammogenic" preparations were relatively inert when injected into ovariectomized virgin mice unless estrogen was administered simultaneously.

MAMMARY GLAND OF THE RHESUS MONKEY

if

mals. Further,

were present in the

gonadotrophins

testicular androgens could been produced, since intact rather than castrated pituitary

have

extracts,

male

mice were used in the assay method of “mammogen by

I.”

These objections could be met, at least in part, the use of adrenalectomized

assay purposes. Unqualified

of

specific

origin

of the concept

hormones

“mammogenic”

animals for

castrated

acceptance

of

pituitary

therefore, not to be justified

appears,

First, during pregnancy the placenta

of sustaining It

such

been

has

the

growth

of

the

mammary

a

sound basis for questioning

is

cept.

a

furnished

with estrogens

capable glands. de

which

distinct

forced feeding.

1940b).

was emptied at mid-pregnancy, promptly followed

mouse

mammary involution

(Newton and Beck,

Second, positive experimental

the

of the afore-mentioned negative findings and indicates that the sex hormones can stimulate mam— in hypophysectomized

animals.

hy

some

In

by

pophysectomized rats, for example, glandular develop ment has been produced injections of estrogen and in combination (Cha and progesterone, either singly

acetate

morro, 1940e), estrogen

or together (Smithcors and Leonard, dipropionate, testosterone (Leonard, (Lyons,

estrone

Simpson,

1943), estradiol 1943),

and

a

desoxycorticosterone

and purified

lactogenic hor

and Evans,

Similar

1942).

results have been obtained in hypophysectomized mice with estradiol dipropionate, desoxycorticosterone acetate,

and progesterone, singly or in various com

binations with each other (Gardner, with

prolactin

and White,

(Gardner in hypophysectomized rabbits treated

1940, 1941a) 1942a,

with

and

194212); estrogen,

rats

glands of these

the mammary

of complicating however,

suggested, rats which

animal

with estradiol benzoate and

Shaw, and Franseen, 1939). Simi not rigid, correlation was

between the extent of mammary

hypophysectomized pituitary,

whereas

of body growth rats treated

lipoid

with

pituitary

on the mammary Moreover,

stimulation

that occurred desiccated

in

cattle

extracts

should have contained “mammogen”)

1941).

of the

loss

of atrophy of its mammary

general, although

and the amount

effect

was stressed

between the weight

and the degree

in the

series of hypophysectomized

were treated

correlation

the

found

disturbances

failure of growth

hormone, the role of nutrition

growth

larly,

metabolic

the

In another

glands (Nathanson,

1939).

evidence contradicts

Yet

animals failed to respond to estradiol benzoate. The

a

When the uterus of

propionate when

the body weight of hypophysectomized

taining

by

mice with intact ovaries

Similar glandular

glands (Greep

(which were without and Stavely,

in intact albino mice on

limited

food intake, the amount of estrogen required to elicit standard growth response in the mammary glands

a

glands of hypophysectomized

mone

of the glands was ob

sectomized rats (Reece and Leonard, 1942). Samuels, and Petersen (1941) succeeded in main

nipples also.

of

stimulation

Reinecke,

Also, gonadotrophic

or pregnant mare serum can maintain the mammary

in

rats

growth hormone was also injected into the hypophy

existence

combination

to hypophysectomized

estrogen alone had failed to elicit mammary

1935), mouse (Newton and Richardson, 1941; Gardner and Allen, 1942), and guinea pig (Desclin, 1939).

hormone from pregnancy urine

of the

this explanation. When “growth hormone” plus estro gen was administered

has

con

removal

(Astwood,

(Reece and Leonard, 1941). responses resulted from testosterone

amply demonstrated that mammary

mary growth

from

resulting

Geschickter, and Rausch, 1937). Subsequent experimental work has given support to

pituitary

growth,

velopment can continue in the absence of the pituitary in the pregnant rat (Pencharz and Long, 1933; Ieffers,

(Chamorro,

attributed to the nonspecific

has been

of inanition

effects

1935). to occur in

animals which were treated

some hypophysectomized

served

contrary, evidence from other sources

the

(Nelson,

The failure of mammary development

the

at

present writing.

On

with estrone

guinea pigs treated

ani

of gonadectomized-adrenalectomized

is

following such

occur

to

either alone or in combination with progestin (Asdell and Seidenstein, 1935); and in hypophysectomized

a

failed

growth

whereas

by

mammary treatment

the adminis

hormone,

adrenocorticotrophic

increased in proportion

to the

degree

striction (Trentin and Turner, 1941). Finally, critical evidence resulting

of dietary re from

new

method of approach has been brought to bear against the

claims for specific mammotrophins

origin.

Unilateral

has been produced estrogen

growth by

of

by

tration

by

tomized immature mice of both sexes

a

48

of pituitary

of the mammary

glands

the direct topical application

to the nipple area.

of

This type of experiment

MAMMARY GLAND OF THE RHESUS MONKEY

nutritional

factors of surgical interference and

disturbances have thereby been

(Speert, 1940b). Three immature

obviated

estrogen-treated breast of the same animal contained rounded 114,

male monkeys

were used,

their

being about 2400 gm. T0 the left nipple of each animal a small amount of estrone was average weight

extremely hyperplastic ducts which were sur

several

by a

the complicating

mantle of connective tissue

dense

(fig.

pl.

has permitted the use of normal intact animals, and

49

18). The local response

of the mammary

gland to the

cutaneous application of estrogen has been confirmed in the

monkey

and Allen,

Gardner,

(Chamberlin,

This was accomplished by “painting” the nipple with an alcoholic solution of estrone con

rabbit

taining 0.05 mg. of the estrogen per cc. of 95 per cent ethyl alcohol. Preliminary experiments with guinea

and Chamberlin, 1941), (Gardner guinea pig (Nelson, 1941a), and cow (Petersen, per

pigs had shown that the most pronounced differential

also some evi sonal communication, 1943). There dence that unilateral mammary development can be

with

this

concentration

of

the

hormone.

When

weaker solutions were used, the rate of growth of the was slower;

nipple

when

estrone were applied,

higher

concentrations

of

occurred

systemic absorption

1941)

demonstrated

been

(Lyons and Sako,

1940;

mouse

is

1942),

produced in the human fraudulent

several

local application of estro

1939), whereas no effect

gens (MacBryde,

products which

tised as “bust developers” (Iour. Amer.

monkey was painted with plain alcohol and served as

1940. I943,

Two animals were

for 75 days; the entire mammary glands were then removed sur so treated

The third monkey was

for only 50 days, but 105 days were then allowed to elapse before the mammae were removed. sections Histologic

gically.

treated

produced

have

appeared on the commercial market from time to time, adver

and both nipples responded. The right nipple of each a control.

in the

similarly

Lewis and Turner,

is

between the two nipples could be obtained

growth

and has

by

daily.

by

applied

1944)

These experiments leave

little room for doubt as

to the mode of action of estrogens

gland.

Med. Assoc.,

upon the mammary

Under simple experimental conditions which

were made of the mammary tissue at the base of the

minimized opportunities for discrepancies in technique and disagreement on interpretations, several workers in different laboratories have obtained similar

nipple; the rest of the gland was prepared as a gross

results in

these

observa

mount.

tions one can only conclude that estrogens their trophic effect upon the mammary gland

produce

spreads

developed than the control.

of the former had a greater area, their

and clusters

similar

asymmetry was greatest

The resultant mammary

in the monkeys which were

for 75 days (figs. 111, 112, pl. 18), but a differ ence between the two breasts was still discernible in treated

the third period

animal,

and whose

which

was treated

mammary

glands

control glands.

In

the

taken

from

(fig.

113,

comparable

Though

estrogen.

these

observa

mammo

Estrogens have merely been proved capable

were not ex

of acting directly upon the mammary

the

a typical section of the latter, only

a

sections

locally applied

tions fail to support the theory of pituitary they still

small duct could be seen, lying

connective-tissue stroma

to cause

in both mammary

existence.

estrogen-treated and

pl.

a single

of

response

trophins,

An equally striking contrast was afforded by the sections

growth

for a shorter

amined until 31/2 months later. Even in this case the area of the left mammary gland was about 50 per cent greater than that of the right. histologic

upon the mammae.

mode of action would be expected

glands rather than the unilateral effect which was produced by

their terminal arborizations.

a

Such

direct

no support can be offered for the

mediation of this effect

pituitary

ducts were wider and had more numerous branches, of end buds were present on many of

a

action. Therefore,

a

tinctly larger and better

The

was dis

estrogen-treated gland

the

by

case

in a loose

18), whereas

region

of

the

channels

may also

do not preclude

exist

action on the breast

is

each

From

variety of species.

through

effected,

their gland.

which

possible Other

estrogenic

but these must await

further experimental demonstration.

A

recent report

by

In

have

Lyons

(1942)

has indicated that

the lactogenic hormone also can act locally upon the mammary

gland.

intraductally,

When this

substance

was injected

through the nipples of rabbits, localiZed

lactation ensued in the injected parts of the glands while the control sectors remained unaffected.

MAMMARY GLAND OF THE RHESUS MONKEY

50

ACTION ON THE NIPPLE

Although their effects

the manner in which

upon

hormones produce gland has been the

the mammary

subject of considerable controversy, general agreement prevails concerning upon the nipple.

the

mode of action of estrogens

N0 claims

have

appeared for other

than a direct effect, even though growth of the nipples animals

was not observed in some hypophysectomized which

had been

injected with estrogens

(Samuels,

Reinecke, and Petersen, 1941). In the vast majority of experiments in which adequate amounts of estro

the estrogen-treated and the control

(alcohol-treated) These measurements included the length of

nipples.

the nipple, the diameter of its base, and the diameter

of the areola. For purposes of comparison, the nipple was considered calculated

Likewise when

animals.

growth of the nipples resulted (Ruinen,

have

been

of the areola, and r its radius.

of two animals which

1932).

nipples

than the pre

conditions in additional

In all,

18 monkeys

absorption

(LI

table

various estrogens

in

to the

nipple area in a variety of oils, ointment

bases,

alcohol (Mussio Fournier, Albrieux, Iadassohn, Uehlinger, and Ziircher,

Iadassohn,

Fierz,

Uehlinger,

and Margot,

Uehlinger,

and Fierz, 1941; Nelson,

sohn, Uehlinger, ized growth

and Bufio, 1937; 1939; Iadassohn,

Iadas 1941a). and Margot have also obtained local

of the guinea pig nipple by the topical of aqueous solutions of testosterone

application pionate,

1938;

and

androsterone,

androstenedione,

pro

androstane

(fig.

The left nipple

and 708)

the right nipple, serving as

with

in which

plain

In two

alcohol.

supernumerary

nipples

were painted with the estro

these also

In one animal (G25), the right nipple to this experiment. The

had been amputated prior

menters have obtained a unilateral nipple response

1937;

(L1

estrogen-treated

animals.

was painted

were present,

ginning

guinea pig by applying

first

were studied.

(0.05 or 0.5 mg. per cc.); a control,

occurred so that after 4 weeks no difference between the two nipples was discernible. Subsequent experi the

the

was painted daily with an alcoholic solution of estrone

genic solution.

On continued

systemic

In

1) that it was considered desirable to study this phe nomenon of differential growth under a variety of

ment of the treated

sufficient

was

represents

on the one hand, and the control

cases

nipple in 8 days.

A

were so studied

and L2), the contrast between the

described in the guinea pig by Zondek in 1935. Per cutaneous application of estrogen resulted in enlarge however,

where

on the other was so striking

_viously mentioned local effects of the hormone upon the mammary glands proper. This finding was first

treatment,

A =nr2,

nipples and areolas

in the treated

more striking

even

areola to be a circle, its area

the

nipples and areolas

nipple areas of various species it has been possible to which

the

by

By topical application of estrogenic hormone to the elicit localized growth responses

r

male rats,

estrogen was applied

inunction to the skin of hypophysectomized

V=%rrr2h,

volume of the nipple,

calculated by the formula the area

as in intact

the formula

by

the

measurements of the nipples and areolas at the be 11.

which

and at the end of treatment are recorded in In 4 experiments (S3, S6, 82, and Sro), in

the

observations were continued

beyond the cessation

for a period

of treatment, the last of these

measurements is included in the table.

The

experiments

groups: 1. Group

I

were

divided

into

five

main

(monkeys L1 and L2). The left nipples for 75 days

of these two immature males were treated

with

a solution of estrone

The supernumerary (L1) was

treated

containing 0.05 mg. per cc. of one of the animals

nipple

similarly

with

the

hormone.

The

dione, andrenosterone, and corticosterone. Similar but

volume of the estrogen-treated and the control nipples

of the rabbit

and the area of the experimental and control areolas

less striking to locally

has been the nipple response

applied estrogens

Lewis and Turner, During

(Lyons and Sako,

1940;

the course of the previously

described ex

periments in which the left nipple of immature male monkeys was painted daily with an alcoholic solution of estrone,

are plotted in figure average

1942).

frequent measurements were made of both

The curves

are based

on the

measurements of both animals at each stage

of treatment. increase

1.

The left nipple underwent

in volume during

a

,

was

radius of its base, and 11its length. In a similar fashion,

group

as well

and its volume

a cone,

accordingly

considering

and guinea pigs, a rather prompt nipple response observed in hypophysectomized

be

where V represents

genic hormone were injected into rats, rabbits, mice, was

to

14-fold

the 75 days of treatment,6

6The supernumerary nipple showed a proportionately greater increase in volume (36-fold).

'

MAMMARY GLAND OF THE RHESUS MONKEY while the volume of the right nipple remained rela tively unchanged. The areola of the left nipple in creased in area

in a similar

although

less

was

then

stopped, but

during

51

measurements

next 85 days. were divided into two subgroups:

periodically

striking

the

were

made

The animals

TABLE II EFFECT OF TOPICAL APPLICATION OF ESTROGENON NIPPLE

(Left nipple and supernumerary treated with estrone; right nipple, control) LEFT NIPPLE (MEL)

RIGHT NIPPLE:(Rum) MONKEY

L1 . . . . . . . . . . . . . . . . . . . . . . ..

1

L2 . . . . . . . . . . . . . . . . . . . . . . ..

75 1

53 . . . . . . . . . . . . . . . . . . . . . . ..

75 1 50

S6 . . . . . . . . . . . . . . . . . . . . . . ..

$2 . . . . . . . . . . . . . . . . . . . . . . ..

Length

Width

Areola

Length

Width

1.5 2

2.5 3

7.5 7

1

4.2

2.5 5

7 11

1.5

2.5 3

7 7.5

1.3

2.5

6

4.3

2.3

7

3

2.5 2.5

8.5 9 6

6.5 4

5 2.5 6

9.5 7 13

4 2.3

12 6

6

15 12

1.5 2.5 4

135 1 50

3

135 1

3.3

50

4 3.5

135

2.5 4 3

2.3 4 4 2.3 2

8 8.5 6

2.5 8.5 5

2 2

3.5

3.5

2.5 2

8 9

8 9

6.5 6.5

8.5

6.5

7

14

5

6.5

9

5

7.5

8.5

12.5 15

5.5

15 16 12

7 6

9.5 14

7.3 6

16 15

8 22

15 10

6.3

15

7 8

20 20

4 4

14

7.3 5.5

61 1

9.8

5.3

651 . . . . . . . . . . . . . . . . . . . . ..

10.5

7.5

61 1

10

7.5 4

19

9.8

G24 . . . . . . . . . . . . . . . . . . . . . ..

16

5

4.3

16

G25 . . . . . . . . . . . . . . . . . . . . . ..

50 1

5.5 2.5 4

G29 . . . . . . . . . . . . . . . . . . . . . ..

1

G32 . . . . . . . . . . . . . . . . . . . . . ..

50 1

3.5

G33 . . . . . . . . . . . . . . . . . . . . . ..

50 1

3.5 4

4.5

G35 . . . . . . . . . . . . . . . . . . . . . ..

50 1

G37 . . . . . . . . . . . . . . . . . . . . . ..

50 1 50

1.5 1.8

6.3 6.5

3 3.3 3.5 4

4.5 4.5 5

6.3

5

6.5

5

fashion, in contrast with the insignificant 2. Group

II

(monkeys S3, S6, 52, and 510). These for 50 days. Treatment

immature males were treated

9

3

8.5 9 12

3 2 2

10

3

12.5

3.5 2

12.5 11 10.5 7.5 13 11

changes in

of the right areola.

6

9 9

9.5 9

3.5 4

6

12.5 9

61 1

3

5

14 10

636 . . . . . . . . . . . . . . . . . . . . . ..

3.2 3.2

2 5

5.5 3.5

628 . . . . . . . . . . . . . . . . . . . . . ..

50 1 50

Areola

5.5 3.3

33 1

G28 . . . . . . . . . . . . . . . . . . . . . ..

0.5 3

Width

2.5

708 . . . . . . . . . . . . . . . . . . . . . . ..

5.2 5.3

Length

14.5

135 1

50

Areola

5 4 2

l

2.5 4

5 2.3

2.5 6

7 7.5 6

$10 . . . . . . . . . . . . . . . . . . . . . ..

the area

SUPERNUMERARY (MIL)

DAY

3.5 4 4 3

15 9 11 8.5 10 9 12

3 3.3

13

2

4.5 4

9 7

6.2

5.5

13

5 5.5

5 4.5

7 13

6

5

10

Group a

3.5 3

9.5 6

II-A

solution

During

13

(monkeys S3 and S6) was treated with containing 0.05 mg. per cc.

of estrone

the 50 days of treatment, the average

volume

of the left nipples, as in group I, undervvent a sharp

MAMMARY GLAND OF THE RHESUS MONKEY

52

r4-fold increase. The control nipples also increased in volume during this period, but to a relatively in degree (fig. 2). When treatment was stopped, the left nipples involuted rapidly during the

significant

following month. After this initial decline, however, the

volume curve leveled off, so that at the end of

85 days the average

volume of the left nipples was still

21/2 times as great as the average 90

Group

(figs. 2, 3). 3. Group animal,

volume of the right

II-B

(monkeys

and $10)

$2

was treated

with a solution of estrone containing 0.5 mg. per cc. The nipple and areolar responses in these animals were similar qualitatively to those in group II-A

no.

III.

This group

708,

mature

a

consisted of a single female

numerary nipple on the right side.

with

a

super

Estrone (0.05 mg.

'

80

70

60'-

30

50L

25

4o—

_--O 2'

2'

E

830'-

a ZIS

2

Z '_

5 8

AREOLA _- - O

L] _1 20—

it _

z

IO

u; L O < n. IO __ u 5

0

2

:5 (1:


5

IO

IS

20

25

3O

35

40

45

50

55

DAYS OF TREATMENT

60

65

7O

75

Frc. 1. The effect of locally applied estrone on the volume of the nipple and the area of the areola

supernumerary

their former

area

within

a month;

but they

tained this size, which was still significantly

of

the average

for the right areolas,

period of observation.

of treat

shrank to one-half main

in excess

to the end of the

receiving treatment with mg. per cc.) for 61 days. unaffected (table II). Group

(monkeys

a

the cessation

and to the

for 33 days, with no signifi size of either nipple or areola

628, 636, and 651). These animals were at various stages of pregnancy while

V

Following

ment the estrogen-treated areolas

in the

the left nipple

to

resulting (table II). Group IV (monkeys

solution of estrone

(0.05

The nipples and areolas were 624, 625, G28, G29, G32,

G33, G35, and G37). This group of young animals consisted of females and male. All had been 7

grew only slightly.

nipple

4'.

than 5 times the average of the pretreatment areas (fig. 3). During the same period the right areolas

cant increase

3

of the left areolas at the end of

area

period of estrogenic treatment was more

5.

The average the 50-day

per cc.) was applied

1

volume

nipples and 5 times as great as the average

of the left nipples before treatment was begun.

MAMMARY GLAND OF THE RHESUS MONKEY

53

receiving intensive estrogenic treatment, in the form

treatment were unaffected. Similarly,

of subcutaneous pellets and oily injections, for periods ranging up to 2 years. The topically applied estrone

areolas

the nipples and were under

of the immature animals which

going treatrnent with estrogen pellets and injections

10

as

so

55

50 (A) ESTRONE o.os MGM/CC 45

IO

35

30

20

MGM/CC

CQNTROL FOR

--

___ __

)

CONTROL FOR(

IO

I5

20

. 25

30

35

40

45

DAYS

50

b

5

..__ --IO

I!)

20

25

30

35

40

pregnant

I

of estrone

males in groups 3

$0

55

60

65

7O

75

60

85

and

was limited

II. The

animals

which

to

the immature

mature female and received

the

same

of the nipple

failed to respond to the topically is

after 50 days’ treatment (table 11). The response of the nipple and areola to the topical

It

was without demonstrable effect on either the nipples or the areolas application

45

TREATMENT STOPPED FIG. 2. The effect of locally applied estrone on the volume

the

_ _ _--.

- ___ __

5

VOLUME

as

A)

(Bl .ESTRONE

OF NIPPLE

IN CU. MM.

25

not surprising

applied hormone.

that the nipples of the pregnant

monkeys and those of the immature animals in group

V

did not increase

in size following the percutaneous

application of estrogen, for these animals were already “saturated” with estrogens.

Therefore

no significant

MAMMARY GLAND OF THE RHESUS MONKEY

54

in the already high titer of the hormone in

increase

the tissues

As

was to be expected.

smooth

a result of the

muscle

bundles

intense estrogenic stimulation to which they had been

key

The vascularity

no. L1.

subjected, the nipple structures had already realized

nipples underwent an increase

their maximal possibilities for growth.

among the different

Chamberlin,

a similar,

served

and Allen (1941)

Gardner,

less

although

striking,

have

were conspicuously

ob

and areolas

lowing treatment of the left nipple with an alcoholic

pl. 19).

A

slight response

of

the

estrogen in mon

striking

the experimental

which varied in degree

animals.

The blood capillaries This

filled with red blood cells.

accounted for the pinkish coloration which the nipples

differential

growth in the nipples of 2 young male monkeys fol solution of estrone.

in

occurred

treated nipple; this was particularly

during treatment (figs. 115, 116,

assumed

Vascular dilatation was also observed in the

experimental nipples of several of the mature animals

was observed

l60 ISO I40

OF AREOLA

I

FOR

5

IO

20

I5

25

35

30

4O

45

50

5

AREA

'Eoiif'laok

Foil

_l_

CONTROL

( X

IN SQ MM.

(A)ESTRONE 0.05 mm

(,C. I \.

ONE

“Owl

c

ai is“

0.5

IO

I5

25

20

30

35

4O 45

50

55

60

65

70

nipple

of

75

80

85

DAYS

were treated in this manner Significant

The effect of locally applied estrone on the area of the areola

human

newborns who

(Speert, unpublished).

histologic differences between the estro

monkeys in groups

I

gen-treated and the control nipples were found in the and

II.

These differences oc

curred most consistently in the subepithelial dilatation treated

was the

increase

of the lymphatic

nipples.

experimental

tissues.

in the number

The connective-tissue stroma of

nipples

increased in quantity

cellularity and appeared to contain of interstitial fluid.

In

some

and

in the estrogen

vessels

a

Outstanding

the

(especially despite

In the

the

supernumerary

no. 708),

the failure of these nipples to increase

each case except

one,

the epithelial

two nipples were indistinguishable.

no. L2, however,

a

out of

6

3

in the nipples of

3.

TREATMENTSTOPPED Flo.

in

size.

coverings of

In monkey

significant difference was observed

between the nipple epithelium of the experimental and that of the control side. in the Malpighian and

the

stratum

Mitotic figures were common

layer of the estrogen'treated nipple, germinativum

had

increased

to

and in

several

times the thickness of the corresponding layer

greater quantity

in the

control

absence

of similar epithelial hyperplasia in the nipples

cases hypertrophy

of the

nipple

(figs. 117, 118, pl. 19).

The

MAMMARY GLAND OF THE RHESUS MONKEY of

This reaction

other animals is unexplained.

the

in

our

The stromal reaction which

monkeys.

in guinea pigs whose nipples were treated by topical application of estrogens (Fierz, and Fierz, 1941). The 1939; Iadassohn, Uehlinger, increased pigmentation which was observed in the

curred in the absence

nipples of estrogen-treated guinea pigs (Davis, Boyn

permeability

occurred uniformly

and Rothman,

ton, Ferguson,

1945) was also absent

55

of significant

oc

epithelial hyper

plasia is indicative of the sensitivity of the lymphatics and capillaries of the nipple to estrogenic stimulation. Estrogens can also produce a specific increase in the of the capillaries of the rat uterus and

Krohn, and Harris,

vagina (Hechter,

1942).

SUMMARY 1.

The mammary line was demonstrated in

key

of 34 days

embryo

(crown-rump

mm.). 2. The mammary gland of of a few

short, poorly

a mon

length

11.3

degree

The the

branched

newborn

consisted

ducts lined

with

of individual

variation was found in the mam

mary gland, little growth occurring during this period. of

3d month

glandular

witnessed a sharp increase in the rate Secretory

development.

usually well established microscopically

was

activity

by the end of

Mitotic proliferation

of

hyperplastic, nonsecretory epithelium.

the 4th month of pregnancy.

3. Extension and branching of the mammary ducts occurred during adolescence, with a resultant in

the gland cells continued to term. At term the mam

in_mammary

crease

The right and left

area.

breasts

mary gland

r2. Removal

grew at about the same rate. 4.

The adult

breast consisted of a flat sheet of mam

mary tissue subjacent to the skin, extending laterally individual

was found

variation

in

identical

physiologic

conditions.

Changes

in

the

studied by means of repeated

and

gland

experimental

were

therefore

biopsies in the same

animal.

no “virginal

of both ovaries as early as the 31st day the breast; glandular

development and lactation proceeded normally.

within

13. Secretory changes occurred in the gland 2 days

after the termination

14. Lactation

the mammary glands of both male and female mon keys under

developed;

of pregnancy had no effect on

into the axilla and caudally below the costal margin. 5. Pronounced

was uniformly

lobules” remained.

large folds

at 60 days.

began within 2 days after parturition.

When lactation was in

of pregnancy

at its height and the breasts

below

the

costal margins,

activity was present in the duct epithelium. rare after the first few days

figures became

hung

secretory

Mitotic of the

14

puerperium, and during advanced lactation they could

monkeys of the Carnegie collection, an incidence of

not be demonstrated at all. Many lactating cells con

about 1.4 per cent. In 6 cases mammary associated with the extra nipple.

tained double or lobulated nuclei.

6. Supernumerary

7. Lobules

nipples

were discovered

in

ducts were

of alveoli were present in only

and postlactational involution of the

15. Postpartum a few of

the male breasts.

mammary different

8. Cyclic changes occurred in the mammary

glands

the

gland occurred irregularly, rates

uniform

in different

progressing at

lobules, in contrast with

development of the gland during preg

of mature females, in relation to the menstrual cycle.

nancy. On the average, the lobules remained engorged

Lobular enlargement, resulting from dilatation of the alveoli, was observed during the premenstruum and

for about 2 weeks after parturition

or after the cessa

tion

processes

Involutionary

became

evident during the 2d week and were complete at the

This change occurred in association with ovulatory

end of 31/2 months. Reduction of glandular tissue resulted in part from atrophy of the cells, and in part

no mammary

cycles;

the postmenstrual

lactation.

period.

gradually

subsided during

of

changes were observed when

ovulation failed to occur. 9. Removal

of

from desquamation

the corpus luteum 5 days after ovula

tion resulted in a rapid shrinkage

of the mammary

lobules. produced no effect on the mam

mary gland.

During

Involution

in animals which

of the cells into the alveoli and

appeared to progress more rapidly had been permitted to nurse their

young than in those

10. Hysterectomy

11.

ducts.

16. the first 2 months of pregnancy a high

whose young were taken from

them at birth.

After fetal

death

in utero, mammary involution

began irrespective of expulsion of the fetus. Involu

MAMMARY GLAND OF THE RHESUS MONKEY

56

were observed following the inter

tionary processes

ruption of pregnancy as early as the 36th day. 17. An unusual, irregular mammary pattern was

(Amniotin) and

a progestogen (progestin or anhydro

Crystalline

hydroxy-progesterone).

progesterone,

in

observed in a pregnant monkey at term, 26 days after

daily doses from 5 to 20 mg., caused mammary growth in castrated females without estrogenic priming. The

weaning her last offspring.

compact,

18. Castration

of mature female monkeys resulted

in generalized atrophy of the mammary gland and the simultaneous

of

development

discrete

nodules. Natural or synthetic estrogens,

byperplastic progesterone,

connective

dense

stroma of castrated

tissue

animals

of the

mammary fibrillar,

loose,

became

with pro

and edematous as a result of,treatment gesterone.

(FSH,

22. Gonadotrophins

Go

and

Follutein,

androgens, and desoxycorticosterone acetate were each

nadogen) resulted in slight to moderate mammary de

effective in preventing

velopment in 2 amenorrheic females. Treatment

nodule formation

when they

were administered in adequate dosage within the first

third animal with

month after castration.

on the breast.

of mammary

19. Stimulation

duced by estrogens, the

Each hor

general pattern of response,

same

consisted of hyperplasia, dilatation,

which

pro—

progestogens, androgens, gonado

trophins, and desoxycorticosterone acetate. mone caused

was

growth

extension,

FSH

of

a

and Follutein had no effect

Mammary

response

to gonadotrophins

could be correlated with other evidence of ovarian stimulation. 23. Testosterone

and

propionate,

testosterone

in

amounts ranging from 5 to 50 mg. per day, each pro duced mammary growth in castrated and intact fe

and branching of the ducts, and growth of the lobules

males. Mammary

atrophy occurred when treatment

and dilatation of the alveoli. Growth

was discontinued.

Androstenediol

by multiplication

was produced in castrated

mature females by 100 r.u.

of an estrogen daily for 50 days. When the ovaries were present, stimulation occurred in a month with only 50 r.u. daily. Larger amounts of estrogen resulted in an increase in the speed and the extent of mammary growth.

Complete

glandular

was pro

development

duced and maintained in castrated

females for periods

up to 30 months by continuous treatment with estro-_ genic injections and subcutaneous implantations of estrogen pellets. The early effects of intense estrogenic stimulation

consisted

epithelium,

followed

in stratification by lobular

growth

of

the

duct

and cystic

dilatation of the ducts. As lobular growth continued, the ducts reverted to normal.

daily, complete glandular

With

5 mg. of estradiol

development was produced

in prepubertal animals in 70 to 85 days. Stilbestrol, in increasing amounts up to 2 mg. per day for a

occurred genized

metaplasia of the mammary epithelium

in one-third monkeys.

of a group

Small

(by mouth)

mammary methyl

and methyl testo

were each without effect. occurred

responses

when

was administered

testosterone

Positive

testosterone

or

concurrently

with an estrogen. When estrogen and androgen were administered sequentially, positive responses

with Amniotin

tained

together

or testosterone

propionate,

testosterone

with

were ob

testosterone,

dipropionate,

but not with methyl testosterone lial proliferation

(by mouth). Epithe— which resulted in heaping of the cells

and the formation

of microscopic papillomas

in the

ducts and alveoli occurred in 2 females which received large doses of testosterone

and testosterone

propionate

respectively. 24. Desoxycorticosterone 10 mg., produced mammary

acetate,

in a daily dose of

development in castrated

females; but a daily dose of 5 mg. had no effect on the breast.

month, produced no effect. 20. Benign

sterone

of highly

estro

of atypical pale

islets

epi

25.

Topical application of an alcoholic solution of

estrone

to one nipple

area

keys resulted in localized,

of prepubertal male mon— unilateral

growth

of the

thelium, resembling the type frequently seen in mam

nipple and areola and the underlying mammary tissue;

mary cysts in the human, appeared among the normal

whereas the control gland, treated

lobules and in the duct linings.

unaffected.

tense

Prolonged

estrogenic treatment failed to produce

and in malig

21. Mammary

the theory of pituitary

mediation of estrogenic effects

upon the mammary gland.

nant change. development

was produced

in cas

trated females by the sequential action of an estrogen

no nipple

with alcohol, was

These observations offer no support for

growth

Similar treatment

in pregnant

animals

injected with large amounts of estrogen.

caused

or in those

MAMMARY GLAND OF THE RHESUS MONKEY

57

ACKNOWLEDGMENTS

The studies on which

phenomena in the macaque; for permitting the use of his active monkey colony for various experiments and

the writer enjoyed the status of guest in the Carnegie

mammary biopsies; for his contagious vigor and en

Laboratory,

Embryological

through

based

the courtesy of

Dr. George L. Streeter, then Director. To Dr. Carl G. Hartman, who suggested this investigation and its conduct, thanks are

due on several

additional

counts:

for

sharing

facilities of his laboratory; for making available lection

in

of preserved mammary

the course of his long-term

a

offered constant help during

the col

specimens acquired study of reproductive

thusiasm. Acknowledgment mental

specimens

Geschickter.

is

this report

is

were

carried out during the academic year 1939—1940, when

obtained

Invaluable

made of several experi

from

assistance

Dr.

Charles

F.

was received from

Mr. Arthur Rever, who performed the injections and helped with the surgical procedures; Mr. Charles Miller and Miss Harriet Caspari, who prepared the sections; and

histologic

Mr. Chester Reather, who

made the photographs and photomicrographs.

LITERATURE CITED

Observations

Carnegie Inst. Wash. vol. 19, pp. 1—44. 1928a. Reactions

Pub.

380, Contrib.

to Embryol.,

by

5.

injections on uterus and mammary glands of ovariec tomized Proc. Soc. and hypophysectomized rabbits. Exper. Biol. and Med., vol. 32, pp. 931—933.

E. B., C. F. Gsscmcxm, and E. O. Rauscn. 1937. Development of the mammary gland of the rat. study of normal, experimental and pathologic changes and their endocrine relationships. Amer. Iour. Anat.,

of immature monkeys (Macacus rhesus) to injections of ovarian hormone. Iour. Morphol., vol- 46. PP-479-519 1928b. Further experiments with an ovarian hor mone in the ovariectomized adult monkey, Macacu: rhesus, especially the degenerative phase of the menstrual

Arums, M.

cycle. Amer. Iour. Anat., vol. 42, pp. 467-487. and E. A. DOISY. 1923. An ovarian hormone. Iour. Amer. Med. Assoc., vol. 81, pp. 819—821. W. U. GARDNER, and A. W. Dmnuz. 1935. Experi

AucHrNcLoss,

z.

gestation.

Iour.

la

la

le

Geburtsh. u. Gyniikol., vol. pp. 13—51. ANcEL, P., and P. BomN. 1911. Recherches sur les fonctions du corps jaune gestatif. ll. Sur déterminisme du d6 veloppement de glande mammaire au cours de de physiol.

et de pathol. ge'n., v0]. 13,

PP- 31—41~ ANDREWS, E., and O. F. KAMPMEIER. male breast.

Surg.,

Gynecol.

30—38. ASCHNER, B., and C. Glucoiuu.

1927. Swellings of the and Obstet., vol. 44, pp.

I.

f.

1911. Placenta, Fotus und Keimdriise in ihrer Wirkung auf die Milchsekretion. Arch. Gynakol., vol. 94, pp. 766—793. onoxs, G. W. Sausaunv, and H. R. ASDELL, S. A., H.

A

le

a

Die Innervation der Milchdriise. vol. 64, pp. 795—810. BAYLISS, W. M., and E. H. Summer. Koordination

der Funktionen

Iahrb.

Kinderheilk.,

1906. Die chemische des Korpers. Ergebn.

physiol., 2. Abt., vol. pp. 664—697. female mon BEDDARD, F. E. 1901. (Exhibit of the skin of key from specimen lately living in the Society’s Garden. Specimen was received September 25, 1900 and died February 19, 1901.) Proc. Zool. Soc. London, vol.

1,

Beitr.

H., and C. D. HAAGENSEN. 1940. Cancer of the breast possibly induced by estrogenic substance. Iour. Amer. Med. Assoc, vol. 114, pp. 1517-1523. Base", K. 1906. Beitrage zur Physiologic der Milchdn'ise.

a

Geschlechtskaraktere.

sécrétoire de glande mam maire hyperplasiée, chez cobaye male chatré, consecu tivement greffe de l’ovaire. Compt. rend. Soc. de biol., vol. 78, pp. 410-412.

5,

sekunda'ren

vol. 61, pp. 373-405. 1915. L'activité

a

die

2,

und

Asrwoon,

I.

ments with theelin and galactin on growth and function of the mammary glands of the monkey. Endocrinology, vol. 19, pp. 305—313. nach Kastration ALTERTHUM, E. 1899. Die Folgezustiinde

6

R'YN-"M‘RH-QN

mm.

mm

Rumor

removal

d.

on normal animals, the eflects of of the ovaries and the efiects of injections of ovarian and placental extracts into the spayed animals.

rhesus:

pp. 87—88. Brr'rmcan, H. F. 1944. Hermaphroditism. Surg., Gynecol. and Obstet., vol. 78, pp. 91—97. BIEDL, A., and R. K6N1osrriN. iiber 1911. Untersuchungen das Brustdriisenhormon der Gravidita‘t. Ztschr. exper. Pathol. 11. Therap., vol. pp. 358—373. f.

S.

(“w-r.

I

and G. W. SALISBURY. 1933. Mammary de velopment in the rabbit. Anat. Rec., vol. 55, suppl. p. and G. W. Sausaunv. 1933. The cause of mammary in the rabbit. development during pseudopregnancy Amer. Iour. Physiol., vol. 103, pp. 595—599. and H. R. SEXDENSTEIN. 1935. Theelin and progestin

la

vol. 32, pp.

f.

Biol. and Mcd.,

249—251. E. OWEN. 1939. Adenocarcinoma of ALLABEN, G. R., and the breast coincidental with strenuous endocrine therapy. Iour. Amer. Med. Assoc, vol. 112, pp. 1933—1934. ALLEN, E. 1927. The menstrual cycle of the monkey, Macacus

1936. Experiments in the physiology of Cornell Univ. development and lactation. Agric. Exper. Sta. Mem. 198. and HAMMOND. 1933. The effects of prolonging the life of the corpus luteum in the rabbit hysterec tomy. Amer. Iour. Physiol., vol. 103, pp. 600—605.

8,

in

Proc. Soc. Exper.

monkey.

SEIDENSTEIN. mammary

la

S.

of normal

I.

B. D.

1934a. Comparison of mammary glands and ovariectomized rhesus monkeys. Proc. Soc. Exper. Bio]. and Med, vol. 32, pp. 246-247. the rhesus 1934b. Growth of the mammary gland

ABERLE,

MAMMARY GLAND OF THE RHESUS MONKEY

gravidique; préliminaire). glandulaire (Note Compt. rend. Soc. de biol., vol. 72, pp. 129—131. BRADBURY, I. T. 1932. Study of endocrine factors influencing mammary development and secretion in the mouse. Proc. phase

Soc. Exper. Biol. and Med, vol. 30, pp. 212—213. BRODY, 8., A. C. RAGsnALE, and C. W. TURNER. 1923. The rate of decline of milk secretion with the advance of the period of lactation.

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S.

1939. The mammary glands. In Sex and internal secretions Allen, ed.), 2d ed., chap. 9, pp. 740—803. Baltimore. and E. ALLEN. 1933. The normal and experimental development of the mammary gland of the monkey

and S. FoLLEY. 1939. The effect of androgens on the mammary gland of the female rhesus monkey. Iour. vol. Endocrinology, pp. 367—372. VARoAs, L. fibroids in hypophysec 1943. Experimental

a

TURNER, C. W. 1934. The causes of the growth and function of the udder of cattle. Missouri Agric. Exper. Sta. Res. Bull. 339.

65

1935. Supernumerary nipples in monkeys. Iour. Mammal., vol. 16, pp. 229—230. 1941. The effect of desoxycorticosterone on the endo metrium of monkeys. Iour. Endocrinol., vol. 2, pp. 311 316.

PLATE

Embryo C 665, crown-rump length 11.9 mm., age. Note milk line and primor-

dorsal

limb bud.

The caudal part of the milk line is not visible in the

X8.

Embryo

ception

age.

C

5.

gross.

Fla.

479, C.-R.L.

Cross

section

11.3 mm., 34 days con-

of entire

embryo,

show-

ing milk lines projecting from‘body wall medial and

buds.

Section

45-2-5;

haematoxylin

X 20.

Frc. 6. Same as figure 5; X300. Monkey no. 34. Mammary gland of newborn. Gross mount; alum cochineal; X12.

FIG. --Frc.

7.-

dium of mammary gland under anterior

to limb

and eosin;

35 days conception

Monkey no. 715A. Section of mammary gland of newborn, showing byperplastic epithelium lining 8.

Fla. 4.

I

ducts.

Haematoxylin and eosin;

X 250.

Qua

iamhwflve.\m%.r\.$n :4...

\ “a...

I

.

..

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‘

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.

1

PLATE

.e

..

\... at... a8. iv:(.1. ‘1“ 3%.... ...t}

I

;

H. SPEERT 1

. t

PLATE

Flo. 9.

Monkey no. 695.

amenorrheic '

female.

2

Mammary gland of mature mount; alum cochineal;

ing center of field.

Gross

X Il/z. FIG. 10. Monkey no. 604. Mammary gland of mature female following intravascular injection with India ink. Note extreme vascularity of lobules. Delicate capillary network surrounds

pale-staining

duct cross

X50. Pro.

II.

A

lactating

Gross

mount; alum cochineal;

monkey.

Pics. 12, 13. Mammary glands of two preadolescent fe males of similar size, showing range of individual variation

in size and development.

alum cochineal;

le/z.

Gross

mounts;

H. SPEERT

PLATE 2

PLATE

Pics. 14, 15. Biopsy specimens of mammary glands of two adult females, obtained 11 days after ovulation. Note

individual

cochineal;

variation.

Gross

mounts;

alum

X 12.

FIc. 16. Monkey no. 118. Typical supernumerary below right normal nipple.

nipple,

3 F10.

mammary 17. Monkey no. 313. Supernumerary gland, consisting of only 2 short ducts, showing re lation to lower border of left normal mammary

gland. Gross mount; alum cochineal; X3. The in cidence of supernumerary mammae in the Carnegie colony

was about

1.4 per cent.

H. SPEERT

PLATE 3

PLATE

4

F105. 18—27. Mammary glands of 10 mature male mon keys, selected from a group of 24. Note individual variation.

Gross

mounts;

alum cochineal;

X3.

H.SPEERT

PLATE 4

PLATE

Flos. 28—31. Monkey no. 612. Biopsy specimens of mammary glands during two successive menstrual cycles, contrasting mounts;

ovulatory

and nonovulatory

alum cochineal;

types.

Gross

X 12.

FIc. 28. Day 24 of ovulatory cycle, 11 days after ovulation. Lobules are enlarging. Note contrast with figures

30 and 31.

5 29. Day 2 of succeeding cycle (previous cycle 33 days), showing further enlargement of lobules and dilatation of alveoli.

FIG.

FIG. 30. Day 17 of nonovulatory sion of lobules and shrinkage

cycle, showing regres

of alveoli.

FIG. 31. Day 1 of succeeding cycle (previous cycle 24 No change. Contrast with figure 29. days).

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H. SPEERT PLATE 5

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PLATE

Pics. 32—34. Monkey no. 646. Biopsy specimens, ing effect of removal of corpus luteum. mounts;

alum

cochineal;

showGross

X 12.

Frc. 32. Day 21 of menstrual cycle, 5 days after ovulation. Lobules are well developed and alveoli distended. Pro.

33.

Note spongy appearance. Five days after surgical removal

containing corpus luteum. lobules.

6 Pro.

of ovary

Seven

days

later,

12 days

of the lobules

after

operation.

has occurred.

Pics. 35—38. Monkey no. 60!. » Mammary biopsy speci mens at various stages of pregnancy. Gross mounts; alum cochineal; Fro.

Note decrease in size of

34.

Further shrinkage

35.

X12.

33 days.

Fro. 36. 68 days. FIG. 37.

97 days.

Pro. 38.

I44

days (parturition).

l ll i l l 4

PLATE

i

I

FL SPEERT

6

f

.

‘_.

'

\

I

:7.

I Q

~48“!

_ 311?}?n ‘4: 'é '1' Y T‘lsy~ 1." ~

PLATE Pros.

39—42. Monkey no. 654. Mammary biopsy specimens at various stages of pregnancy. Haematoxylin and

eosin;

X 100.

FIG. 39. 23 days. FIG. 40. 95 days.

7 FIG.

41.

Pro.

42.

128 days.

157 days. Pro. 43. Same as figure 42, showing mitotic figures. haematoxylin;

X1500.

Iron

PLATE 7

H. SPEERT

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c. 1) 133.12

. 4

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‘

PLATE F105. 44, 45. Monkey no. 636. Mammary biopsy specimens before and after artificial interruption of preg-

inancy at 36 days. X 12.

Gross

mounts;

FIG. 44. At 36th day of pregnancy. Flo. 45. Fourteen days later, after

alum cochineal;

of

Mammary biopsy speciabortion

X 100.

46.

at 60 days.

At

60th day of pregnancy.

at term,

showing effects of recent lactation.

Haematoxylin and eosin; PK].

mens before and after operative

Haematoxylin and cosin;

FIG.

FIG. 47. Two days later, after operative abortion, show ing secretory activity of gland. Flo. 48. Monkey no. 117. Mammary gland of pregnant animal

interruption

pregnancy.

Fics. 46, 47. Monkey no. 680.

8

X100.

gland, 49. Monkey no. 665. Lactating mammary showing lobulated nuclei and binuclear cells. Sec tion 6 microns thick; iron haematoxylin; X 1750. ,

.c. OI

n 0...: _...-'._.-n .;¢. final-“'4'. £1,