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Hypophysectomy and its effects on male reproductive organs in a wild mammal with annual rut (Citellus).

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RYPOPHYSECTOMY AND I T S E F F E C T S ON NALE
REPRODUCTIVE ORGANS I N A WILD 3lANlf AL
W I T H ANNUAL RUT (CITELLUS)
L. J. WELLS AND E. T. GOMEZ*
Department of Anatomy and Department of Dairy Husbandmy, Universit!y
of MissouTi
T\\'O TEST F I G U R E S .4XD ONE PLATE ( E I G I I T F I G U R E S )
INTRODUCTION
The efTects of liypophysectomy on reproductive organs of
male mammals with an annual sexual cycle have not previously been investigated, to our knowledge. The senior author
has for several years centered his attention upon ceproductive organs of the male ground squirrel (Citellus triclecemlineatus) with the hope that some knowledge could be gained
concerning the factors responsible for cyclic sexual activity
(Moore et al., '34; Wells, '33, '35 a, '35 b; Wells and lloore,
'36; Zalesky and Wells, '37). These studies indicated that
the anterior pituitary gland is definitely related to the aiinual
sexual cycle in the male, and this observation was supported
by results of gross and microscopical studies of the pituitary
gland (Nelson, '36). The object of the present investigation
was to determilie the character of sexual activity in males
experimentally deprived of their pituitary glands. The present paper is the first of a series of reports concerning hypophysectoniized ground squirrels, and the effects elicited by
various hormonal agents in hypophysectomized males mill
be considered later by the writers. We wish to thank Dr.
Aided by a grant from the Coiiiiiiittee for Research in Problems of Sex,
National Research Council.
* Contribution froin the Missouri Agricultural Experiiiieiit Station, J o u m s l
Series 110. 521.
013
214
L. J. WELLS A N D It. T. GOMEZ
Carl R. Moore, Dr. &I. D. Overholser and Dr. C. W.Turner
who have critically read the manuscript of this paper ; also,
Miss Helen Z. Hunt who drew text figures 1aiid 2.
METHODS
Seventy operated males and twenty-eight untreated controls were employed in this study, yet reproductive organs
froin only thirty-one operated and nine control animals were
preserved for detailed study. Early postoperative mortality
was high (56% ) ; however, thirty experimental animals lived
until sacrifice, occurriiig 3 to 5 months after operation, and
only one male reported in table 1 died previous to the date
planned by us. Experimental and untreated males were kept
in adjacent wire cages placed in a steam heated and skglighted laboratory room. Their diet consisted of mixed
grain, Purina dog chow, fresh lettuce, whole milk, salt and
water.
The surgical technique finally adopted by us, essentially a
modification of the method of Smith and White ('31) aiid
White ('33), involved an oral approach to the pituitary. The
animal, following access to unlinlited food and water, was
given an intraperitoneal injection of iiembutal in sufficient
quantity t o induce about SOY& narcosis for a period of about
2 hours. Sub-lethal doses that prolonged narcosis f o r a period
longer than 2 hours greatly increased the hazards of postoperative recovery. The animal was placed on its back oil
the operating board (fig. l), and complete surgical anesthesia
was secured by the cautious periodic use of small amounts of
ether. The physiological effects of nembutal on blood pressure, and the use of only small quantities of ether, tended to
reduce the frequency and severity of hemorrhage. The operating board was then inclined about 20" from the horizontal,
so that the animal's head was lower than the rest of the body.
This procedure was adopted in order to keep the amount of
heniorrhagic blood, flowing by gravity to the larynx, a t a
minimum. The mouth was held open by rubber bands, which
were looped around upper and lower incisors a i d attached to
+ o + o o w
OROUP
NUMBER O F ANIMALS
MONTH KILLED
SIZE O F PITUITARY
FRAGMENTS. ESTIMATED PE& W l i T OF
TOTAL HYPOPHYSIS
BODY WEIGHT IN
QRAYS
Weight in grams
Quantity of
spermatozoa
Weight in grams
4 pithelial height
'in' mera
o o o o o c
Weight in grams
Epithelial height
in mlcra
Weight in grams
Epith~lialheight
in micra
o o o o o c
sz
u1rp
o m
rpw
LU
Weight in grams
DUCTUS DEFEBENS
EPITHELIAL HEIGHT
gg
Epithelial height
in micra
o w
Y ?
L U P
IN MICRA
______.
-
rpo
Epithelial height
in micra
e
216
1,.
J. WELLS AND E. T. GOMEZ
the board. The tongue was kept outside the surgical fielcl by
mild tension of a rubber band against the lower incisors. The
soft palate was bisected inferiosuperiorly as far as the bony
palate by means of a scalpel, and the bisected halves were
held iii lateral positions by slight tension of rubber bands
on blunt wire retractors. Adrenaline chloride was used as a
hemostatic agent, when needed, by applying cotton plugs
soaked in the solution directly upoii the source of hemorrhage.
A circular hole about 1.5 mm. in diameter was bored thi-ough
the sphenoid hone, opposite and ventral to the pituitary gland,
hy means of a dental drill (fig. 2 ) . The dural sheath was thus
Fig. 1 Diagram
showing
animal
n iichoretl t o operating board and pre-
p:ire(l f o r pituitary removal.
x xo.
D
5P
R
05
Fig. 2 Diagram showing the oral
approach used in pituitary reinoval.
TI, drill hole i n sphenoid bone; O.S.,
0s sphenoidale; R., retractor; S.P., cut
edge of soft palate; T., tongue. X 1.
exposed, and its ventral wall was slit with a sharp dissecting
needle. The entire pituitary gland, exclusive of the stalk, was
removed through a glass canula by negative pressure ; bleeding at this stage was rarely more than slight, but it could be
controlled by direct application of adrenaline chloride. One
of us watched the fragments of pituitary enter the canula, and
estimated the amount of the gland actually removed. Since
the surgical field was not a blind one, we could usually tell,
by direct observation, the approximate amount of the gland
removed. The stalk was occasionally drawn into the opening
of the canula, but the magnitude of negative pressure was
JIYPOPEIPSECTOMY IN A W l L l ) MAMhlAL
21'7
kept at a level low enough to prevent destructioii of the stalk
and injury to the diaphragma sella. The bisected soft palate
was then replaced to its normal position without the aid of
stitches, and the animal was removed from the operating board.
Alnch post-operative care was required t o bring the operated animal through early crises. While still in a state of
narcosis, the animal was kept with its head higher than the
rest of the body, so that blood and otlier fluids oozing into
the nasopharynx would not drain into the larynx. If the
animal succeeded in living for 48 hours after the operation, it
was likely to live f o r a period of months. Early post-operative
mortality was preceded by symptoms suggesting hgpoglycemia, which has been reported in hypophysectomized
mammals, particularly when the animals were in a fasting
state (Braier, '31; R6, '31; D'Amour and Keller, '33; Fujimoto, '32 ; Corkill, Marks and White, '33 ; Smith, Dotti, Tyndale and Engle, '36; Shapiro and Pincus, '36). As a precautionary measure to prevent the occurrence of hypoglycemic
crises, dextrose was injected subcutaneously twice daily for
the first 2 days and supplied in the drinking water for a t least
1week. When hypoglycemia had already developed in spite
of our precautions, an extra subcutaneous injection of dextrose
usually relieved the symptoms.
Both operated and untreated males were examined at intervals of about 2 weeks, for the purpose of determining the
maci-oscopic condition of their reproductive organs. Testes,
epididymides and bnlbar gland were examined by manual
palpation, and the presence or absence of scrota1 pigment was
observed.
At autopsy, the following procedures were used in a'koutiiic
manner. The animal was killed with an overdose of chloroform, and weighed. Reproductive organs were removed,
weighed while fresh, and fixed in Bouin's picro-acetic-formol
solution. A smear of fresh epididymis in physiological saline
solution was examined for spermatozoa. The brain was
cautiously removed, care being taken to prevent a destruction
of the dorsal wall of the dural sheath. The sella tnrcica 11-as
218
L. J. WELLS A N D E. T. GOMEZ
macroscopically observed for the purpose of determining
whether pituitary fragments existed. Regardless of the resiilts of these macroscopic observations, the sphenoid bone
was cai~efullyremoved without disturbing the sella region aiid
fised in Bouin’s solution. Following fixation, the sphenoid
bone was decalcified i n either 1Sluller’s fluid or 5 % nitric acid i n
alcohol. Serial sections of the sphenoid region were cut at
10 p, stained with hematoxylin and eosin, and examined microscopically for pituitary fragments.
The following method for estimating the quantity of pituitary tissue in pituitary fragments was used; this method was
suggested to the writers by Dr. R. T. Hill of Yale University,
in a personal communication (see also Gomez, Turner, Gardner
and Hill, ’37). I n serial sections of the sella, the largest seetion of pituitary tissue x7as measured with the aid of an ocular
micrometer ; two measurements of the diameter of this section,
a t right angles to each other, were made. These two diameters
were then reduced t o millimeters. The third dimension was
determined in millimeters by counting the total number of
the 10-p sections containing pituitary tissue. Estimated
volume of the fragment in cubic millimeters was then determined by multiplying the three dimensions. The same proceclure was followed in estimating the total volume of the
entire hypophysis of a normal male. Estimated size of the
fragment was then expressed a s per cent of the total hypophysis. This method gives no more than an approximate estimate
of the size of the fragment. It is probable, however, that the
fragments actually contained less pituitary tissue than is indicated by the estimates, and it seems rather certain that the
fragments had no more than the estimated volume.
Six micra sections of reproductive organs from each of the
forty autopsied animals were stained with hematoxylin and
eosiii, and studied. Sections of the testis were examined, in
order t o determine the character of the germinal epithelium.
The qualitative character of secondary sexual organs was
microscopically studied and tabulated, while the epithelial
height was measured with an ocular micrometer. Five ocular
HYPOPHYSECTOMY I N -4 WILD NAMMBL
21 9
measurements of the epithelium mere made, care being taken
to avoid areas cut tangentially, and an average of the five readings was recorded.
RESULTS
Reproductive organs from normal males of this species have
been studied previously by one of us at monthly intervals
during five complete annual cycles. This experience has made
possible the judicious planning of operation and autopsy dates
at crucial stages in the sexual cycle.
Hypophysectorny performed d u r h g t h e breedi.ng season
Four animals hypophysectomized soon after collection from
the field in early -4pril survived long enough t o be of interest.
One testis of each was removed on the clay of hypophysectoiny
and weighed, average testis weight for the group being 0.8175
gm. Epididymis of each contained many spermatozoa which
were motile in saline solution. After periods varying from
25 to 36 days, these males were killed. Pituitary fragments
mere detectable only in microscopic sections but were present
in each animal. The estimated size of fragmenbs ranged from
0.2% to 17.00/0,the average for this group being 6.374 (group
A, table 1).
The remaining testis of each had undergone regression aiid
was found to be small, flabby and abdominal in position. Average weight of testes from operated males was 19.1% as great
as the average weight for unoperated controls (groups A and
R ) . Testes from operated males contained neither spermatids
nor spermatozoa, while those from controls exhibited many
(figs. 3 and 4).
Accessory reproductive organs of all operated animals i\-erc
found at autopsy to have undergone pronounced regression.
Both gross and microscopical studies indicated that these
organs were essentially similar to those from castrated ground
squirrels (Wells, '35 a). The prostate gland normally stoyes
no secretion in this species, and for this reason it is perhaps
the best indicator of the functional status of the accessory
220
L. J. WICLIJS A N D E. T. GOMEZ
reproductive system. Average prostate weight for hppophysectomized males i n group A was 10.8% of that for unoperated
controls in group B. Average height of prostatic epithelium
in p m i p A was only 41.0% a s great as that in group B. These
quantitative differences a r e move strikingly demonstrated by
organs that store secretion. F o r example, average weight of
seminal vesicles in the control group B was 30.4 times greater
tlian that i n the hypophysectomized group A.
at i c 11c I- i o (1
Twenty-three males hypophysectomized during October and
Koi-ember lived long enough to qualify for our present consideration, i.e., they survived for 3- to 5-month periods until
sacrifice which occiirred at a time when each of seven unoperated controls showed spermatozoa. Only four of the
twenty-three possessed no trace of pituitary tissue, and lhe
other nineteen exhibited small pituitary fragments of varying
size.
I . Atlailts with i w o l v t r d rcywoductivr orgam. Only one
of sis operated adults survived long enough for our consideraIion. This aninial was hypophysectomized on November 22114
at ii time when manual palpation indicated testes to be abdominal in position and accessory organs non-functional. Following a period of 103 days, the male was killed on March 5th.
A pituitary fragment estimated to be no more than 12.2%
of the total hypophysis was found in serial sections (group I,
table 1).
Reproductive organs of this hppophysectomized adult failed
to inidergo renewed development at the season when it occwrred i n nnoperated males (groups I and L). The testis
~t7assmall, flabby and abdominal in position, and contained
iwither spermatids nor spermatozoa (figs. 10 and 9 ) . Testis
weight was only 16.3% of the average weight of testes from
fi\-e unoperated controls. Accessory organs like-wise failed
to inidergo normal cievelopnient, remaining in a non-functional
011 (1it i on.
17yyop hy s is re i n o t*t i 1 d it I- iuq as 11c i
(4
w
H Y P O P H Y S E C T O M Y I N A WILD M A M M A L
221
2 . I m m a t u r e males.
Twenty-two animals operated in
October and November, after attaining an age of 5 to 6 months
and a body w%ightequivalent to that of mature males, survived
long enough (89 t o 155 days) to qualify for consideration.
No pituitary fragments were detectable in four males. I n
each of these animals the entire reproductive tract was dccidedly immature, while that of unoperated controls was either
at a stage of maximal development (testes) or approaching a
fuiictioiial peak (accessory organs). These differences are
~.epresentedin table 1, groups K arid L, but the microscopic
character of the testes should be mentioned; testes of these
hypophysectomized animals invariably showed spermatogonia
a i d spermatocytes with apparently normal morphology, but
they contained no spermatids or spermatozoa (figs. 5 and 9).
Reproductive organs from these four hypophysectomized
males scarcely, if at all, were distinguishable from those of
normal males killed at the time of hypophysectomy. Therefore, our data suggest that hypophysectomy resulted in no
actual regression of reproductive organs, but caused them to
remain in the same infantile condition prevailing at the time
of operation.
Males possessing pituitary fragments. There were eighteen
animals of this type. On the basis of sexual development, they
fall logically into the two following classes, 1) those failing
to produce spermatozoa, and 2) those prodncing spermatozoa.
Reproductive organs from twelve of these animals (66.6%)
i*esembled,in the main, those from animals with no detectable
pituitary tissue. Testes failed to descend to the scrotum,
remained small and contained neither spermatids nor spermatozoa (figs. 8 and 9), while accessory organs remained infantile. Detailed observations are presented in table 1, and
i*eproductiveorgans from these hypophysectomized males may
he compared with those from unoperated animals in the appropriate control groups as follows : groups C and D ; E and
F ; H and L. Group averages for the estimated amount of
pituitary tissue were 7.5% and 9.776, but estimates for individual animals varied from 2.1% to 21.7%.
-7 9.)
-I-
L. J. WELLS A X D E. T. GOMEZ
I n the other six animals (33.3'j/c), testes descended into the
Scrotum, attained a large size and produced spermatozoa wl~ich
were revealed also in epididymis smears (compare groups G
ancl L) (fig. 7). Accessory organs did not attain a breeding
condition, but they showed gross and histological signs of
stimulation by male hormone. Estimated amounts of pituitary
tissue for individual animals varied from 2.3% t o 20.1%.
3. Tmplantation of fresh rat h y p o p h y s r s . Four of the male
yround squirrels which were hypophysectomized while immature during November were selected for this experiment because they showed signs of being completely hypopliysectomized. On Februai.p 15th when untreated controls had large
scrota1 testes, these four Inales had abdominal testes and f o r
this and other reasons Rere thought t o possess no pituitary
tissue. On this date, one testis was removed from each; no
spermatozoa were found upon microscopical study of sections
from these testes. Kach animal received one r a t anterior
pituitary daily for 30 days. The anterior lobe was hashed
with scissoi*s,suspended in a minimum amount of sterile saline
solution and injected intramusciilarly in the legs of the recipient ground squirrel. On the day following the last implantation, March 16th, the ground squirrels were killed. Two
of them showing marked stimulation of all reproductive organs
were found to actually possess hypophysis fragments of their
omn and therefore are not listed in table 1,however, the other
two showed 11o hi s t ologically detect able pit 11it a r y fragments
in their sellae.
I n table 1, reproductive organs from the two completely
hppophysectomized males (group J) may be compared with
those of groups K and L in which the animals received 110
pituitary implants. It will be seen that the males receiving
rat pituitary implants had large testes with spermatozoa (fig.
6) and accessory organs exhibiting signs of stimulation by
testicular hormone ; yet, these accessory organs definitely did
not attain a functional breeding level.
H Y P O P E Y S E C T O M Y I N A WILD iWAJI3IAL
223
DISCUSSION
In this study, we have experimentally removed the hypophysis from males of an annually-breeding wild rodent to see the
effects on reproductive organs. The surgical approach was
such that the operation was not a blind one and the pituitary
stalk mas left intact. We have checlred the success of the
operation by a study of serial sections of the sellae, and estimated the maximal amount of pituitary tissue possible in cases
of incomplete removal. It is probable that many of our incompletely hypophysectomized animals actually had less
pituitary tissue than the amount estimated.
Results of our experiments indicate that sexual activity in
the male ground squirrel is prevented by the absence of the
pituitary gland, and that it either may or may not be prevented by incomplete hypophysectomg.
The animals with incomplete liypophysectomy are of particular interest, since previously it had been found (Wells, '35 a,
and unpublished observations) that the intact pituitary from
males of this species has little gonadotropic potency during the
non-rutting period; it is certainly noteworthy that six immature inales (33.3%) were able to produce spermatozoa, even
though rough estimates indicated that they had no more than
from 31.3% t o 20.1% of the entire pituitary gland at autopsy.
The above observation makes us feel that the presence of tiny
fragments of anterior lobe tissue should not be considered
of little import when interpreting results of experiments in
which hypophysectomized mammalian males are the test animals. It is true that 66.6% of the immature incompletely
hypophysectomized males did not undergo sexual development, but other inales with pituitary fragments as small as in
these did.
Our data also show that fresh rat hypophyses may induce
spermatozoa formation and a release of enough testicular
hormone to cause stimulation of accessory organs in immature
animals entirely deprived of their own hypophyses (two
cases). This has also been accomplished in the intact immature male (Wells and Moore, '36).
22.4
I,. J. WELLS A N D E. T. GOMEZ
SVTMMART A N D CONCLUSIONS
Sexual developmeiit was prevented by complete hypophysectoniy in immature male ground squirrels ( Citellus tridecemlineatus), and either was or was not prevented in immature
animals following incomplete hypophysis removal. It is snggested that the presence of tiny pituitary fragments should
not be considered too lightly when interpreting results of
experiments in Tvhic+hthe hypophysectomized mammalian male
is thc test animal. Incomplete removal during the non-rutting
period prevented a renewal of sexual development in one
adult. Hypophysectomy for periods of approximately 1 month
during the breeding season rendered the reproductive organs
atrophic. Daily implantation of fresh r a t hypophyses induced
spermatozoa formation in two completely hypophysectomized
immature males.
L I T E R A T U R E CITED
BRAIEEL,
R. 1931 Exchanges azotes et glgceinie des chiens hypophysoprives a
jeun. Coinp. Rend. Soc. de Biol., T. 107, p. 1195.
C‘ORKILL, A. R., H. P. MARKSA N D W. E. WHITE 1933 Relation of the pituitary
gland to the action of insulin and adrenaline. J. Physiol., vol. 80, p. 193.
D’Aivourt, M. C., AND A. D. KELLE 1933 Mood sugar studies following hypophysertoniy and experimental lesions of hypothalamus. Proc. Soc.
Exp. Biol. and Med., rol. 30, p. 1175.
PI:JIBIOTO,
Y. 1932 Ueber den Einfluss der Hypophyseiiverletzung auf den
Rlutzuckerspiegel. Folia Pharmacol. Japon., Bd. 15, S. 10.
GOXEZ,E. T., C. W. TURNER,
W. U. GARDNF~G
AND R. T. HILL 1937 Oestrogeiiic
treatment of liypophysectomized male nrice. Proc. Soe. Exp. Biol. and
Med., vol. 36, p. 287.
HARTMAN,
C. G., W. M. FIROR
AND E. M. K. GEIL~ING1930 The anterior lobe
and menstruation. Am. J. Physiol., vol. 95, p. 662.
HOVSSAY,
B. A., AND A. BIASOWI1931 The hypophysis, carbohydrate inetabolisin
and diabetes. Endocrinol., vol. 15, p. 51 1.
~ ~ O O R FC
, , . R., G. F. SIIIMOXS,
L. J . WELLS,M. ZALESKY AXD W.0. NELSON 1934
On the control of reproductive activity in a n annual-breeding maminal
(Citellus trideceinlineatns). Anat. Rec., vol. 60, p. 279.
NEISOX, W.0. 1936 The hyl’ophysis of the ground squirrel (Citellus tridereinlineatus) under normal and experimental ronditions. Anat. Rec.,
vol. 64, supplement, p. 34.
Rk, P. Jf. 1931 Aminoacideinia experimental e hiperglueeniia por inyeceibn de
gliroeola eu 10s perros hipofisoprivos. Rev. Soc. Argent. Biol., t. 7,
1’. 503.
HYPOPEIYSECTOMY I N A W I L D M I J I J I A L
223
SHAPIRO,
R., AND G. PINCUS1936 Pancreatic diabetes aiid hypophysectomy in
the rat. Pror. SOC.Exp. Biol. and Med., vol. 34, p. 416.
SJIITH, P. E., L. DOTTI, H. H. TYNDALEA N D E. T. ENGLE 1936 Effect of
hypophysectoiny 011 blood sugar of rhesus monkeys. Proe. Soe. Exp.
Biol. and &led., vol. 34, p. 247.
SMITH,P. E., AND W. E. WHITE 1931 Effect of hypophysectomy on ovulation
and corpus luteum formation i n the rabbit. J. Am. Med. Assoc., vol. 97,
p. 1861.
WELLS, L. J. 1934 Sexual periodicity in the male ground squirrel (Citellus
tridecemlineatus). Anat. Rec., vol. 60, supplement, p. 53.
1935 a Seasonal sexual rhythm and its experimental modification in
the male of the thirteen-lined ground squirrel (Citellus tridecemlineatus). Anat. Rec., vol. 62, p. 409.
-___
1935 b Prolongation of breeding capacity in males of an annualbreeding rodent (Citellus tridecemlineatus) by roustaiit low temperature. Anat. Rer., vol. 64, supplement, p. 138.
WELLS,L. J., AND C. R. MOORE 1936 Hormonal stimulation of spermatogenesis
i n the testis of the ground squirrel. Anat. Rec., vol. 66, p. 181.
ZALESI~Y, M., AND L. J. WELLS 1937 Experimental studies of the thyroid.
I. Effects of thyroidectomy on reprodurtire organs in males of an
annual-breeding grcuud squirrel. Anat. Rec., vol. 69, p. 79.
PLATE 1
ESPLANATION OF FIGURES
(All sectioiis cut at G
p ant1
magnified
x
1GO)
3 Normal testis surgically removed from aiiimal 1 lG4 on March 30th. Speriiiatozoa present.
4 Rcmainiiig testis of animal I164 r e i i ~ o r c ~
a lt autopsy 011 May 5th, following
:I 3G-day period of hypophysectomy. No spermatids o r spermatozoa were fotiiid.
Xoriiial males a t this time of the year have large and spermatic testes.
5 Testis of animal 1112 which was totally hypophysectomized f o r 4 moiiths
:nit1 killed on March 16th. No .ipcrmatids o r spermatozoa.
C,
Testis of airimal 1107 which mas completely hypophysectomized for 4
iiioiitlis. This animal receivcd oiie r a t pituitary daily f o r 30 days preceding
autopsy oil March IGth. Rptwnatozoa present.
7 Portion of testis from aiiiinal 1113 mliich nas hypopliysectomized f o r 4
iuoiitlis and killed oil March 16th. A Siil~llpituitary fragiiieiit estimated to bc
110 more thaii 5.3 yo of the entire liypophysis m-as found.
Spermatozoa present.
8 Testis of :tnimal 1114 which was hypophysectoinized f o r 4 moiiths a i d killed
on March 1Gth. A pituitary fragment estimated t o be no more than 10.9% of
tho entire hypophysis was found. No spermatids or spermatozoa.
9 Testis of a. iioriiial male killed March 5th. Spermatozoa present.
10 Testis of aiiiinal 1122 wliich was an adult with involuted reproductive
orgaiis nlien Iiypol~hysectomized011 R-ovember 0211d. Aiiimal killed on March 5th.
A pituitary fragment estimated t o be iio more tliaii 12.2% of the total liypophysi-,
was found. No spermatids or spermatozoa.
PLATE 1
HTPOPHYSECTONY I N A WILD MAMMAL
Id.
J. WE,LLS A N D E. T. GOME2
227
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