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Effects of hypophysectomy on the reproductive system of salamanders.

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EFFECTS O F HYPOPHYSECTOMY ON THE
REPRODUCTIVE SYSTEM O F
SALAMANDERS1
R. K. BURNS, JR., AND ADRIAN BUYSE
Anatomy Laboratory, School of Medicine and Dentistry, University of Rochester
FIVE PLATES (TWENTY-SIX FIQURES)
1. INTRODUCTION
The diverse and remarkable effects that follow removal of
the hypophysis in vertebrates were first discovered through
the pioneer experiments of Adler ( '14),P. E. Smith ( '16),
and B. M. Allen ( '16), upon amphibian embryos. When the
rudiment of the anterior hypophysis is destroyed o r removed
from the frog embryo, the organism may survive indefinitely,
but its subsequent development is profoundly modified. I n
the absence of the stomodaeal contribution to the hypophysis,
the posterior lobe of the organ fails to differentiate normally,
and the development of the thyroid gland is impaired. As a
result, the processes of growth and differentiation are retarded and the animal fails to metamorphose, retaining
permanently its larval form. There is also a distinctive
change in coloration because of the failure of the pigmentary
system to develop and function normally. The tadpole assumes a characteristic silver-white color, due to decreased
formation of pigment and a contracted condition of the
melanophores. For a more extended treatment of these early
results and f o r bibliography, the reader is referred to the
monograph of Smith ( '20).
It may seem strange at first that in these early experiments
no effects upon the reproductive system were noted; however,
For the photomicrographs that illustrate this paper, the authors are indebted
to Mr. M. C. Orser.
333
THE ANATOMICAL RECORD, VOL. 51, NO. 2
334
R.
r<.
BURNS, JR., AND ADRIAN BUYSE
a retarded condition of one system would probably be unnoticed where general retardation of the whole organism
prevailed. Following upon the recent demonstrations in
mammals of the fundamental dependency of development
and function of the reproductive system upon the anterior
hypophysis, it was established by the results of many workers
that the same conditions prevail in lower vertebrates,
especially in amphibians.
The recent literature on this subject has been reviewed in
a paper dealing with the administration of anterior hypophysis, in extract form, to the immature larvae of salamanders (Burns and Buyse, '31) and our results may be
briefly outlined. When an aqueous alkaline extract of mammalian anterior hypophysis is injected regularly into young
larvae, there are pronounced effects upon gonads and reproductive tract. There is a great increase in growth of the male
gonads, with onset of maturation of the germ cells, followed
by secondary effects upon ducts and cloaca. I n the female
the results are less obvious, but there is premature maturation of a certain number of ova. This has a limiting effect
upon the future size of the ovary, because of the untimely
shortening of the multiplication period of the primitive ovogonia. The same results follow homoplastic implantation of
the whole hypophysis (Burns, '30). The results show that the
gonads, and secondarily the accessory parts, are very susceptible to stimulation by active substances in the anterior
hypophysis of more mature animals. By corollary, opposite
effects should follow extirpation of the hypophysis, especially
in immature animals. Such a result, in amphibians, has been
reported by Woronzowa and Blacher ( ' 3 0 ) , who describe
inhibition of development in the reproductive system of immature specimens, and retrogression in the adults of three
European salamanders, following hypophysectomy.
I n the course of our own experiments, just referred to, a
considerable number of liypophysectomized individuals of the
western 'axolotl' variety of Amblystoma tigrinum were available, following removal of the gland f o r implantation pur-
HYPOPHYSECTOMY I N SALAMANDERS
335
poses. Those which survived operation long enough to allow
for definite changes in the reproductive system comprised a
group of twenty-nine individuals, four of which were adults,
ranging in size from 19 to 22 em. The remaining twentyfive were half-grown animals, from 12 to 14 em. in length,
hypophysectomized at an age when the gonads were yet immature and the accessories but slightly differentiated. These
animals, autopsied at intervals up to one year after hypophysectomy, form the material of this paper.
2. OPERATIVE METHOD AND SUBSEQUENT HANDLING
Since the animal used is a perennibranchiate form, a dilute
solution of chloretone served as anesthetic. Access is obtained through the roof of the mouth. The base of the
cranium is covered only by the oral mucous membrane, and
after removing an area of the membrane, the hypophysis can
usually be seen through the bone as a small white or faintly
pink nodule. The bone is easily penetrated with a dental
drill, which makes a smooth opening. When the aperture has
been made, pressure on the bone causes the hypophysis to
protrude slightly, and the stalk can be pinched off. Usually
there is little bleeding. A drop of a 2 per cent solution of
mercurochrome is placed in the wound as a precautionary
measure.
The mortality after this procedure is only about 12 per
cent. The animals recover from the effects of anesthesia in a
few hours, and by the time activity is recovered have assumed
a parchment-like, or silver-white color (fig. 1). This phenomenon is the invariable result of a successful hypophysec..
tomy in amphibians (for recent treatment, see Klatt, '31).
For a few days operated animals are sluggish and indifferent
to ordinary stimuli. They soon resume feeding, but are usually less active than normal animals. Those which survive
the first week usually live indefinitely. Growth is not permanently inhibited in animals hypophysectomized at this stage,
but there is a setback during recovery. All animals kept
longer than four months after hypophysectomy show notable
336
R. K. BURNS, JR.,
AND ADRIAN BUYSE
increases in length and weight. After several months, animals hypophysectomized at a length of 12 to 14 em. had attained a length of 20 em.-well within the limits of adult size.
Not all become so large, however, within the specified time.
Needless to say, hypophysectomized individuals fail to metamorphose, although most normal animals do so within a few
weeks after removal from their native environment.
3. CONDITION O F T H E REPRODUCTIVE ORGANS I N IMMATURE
SPECIMENS AT HYPOPHYSECTOMY (CONTROLS)
I n these salamanders the gonads differentiate early in
larval life, but the duct system and cloaca remain indifferent
much longer. The miillerian and wolffian ducts in both sexes
are straight, slender, unpigmented tubes, and it is not until
some time after metamorphosis that rapid differentiation
begins. Both ducts then increase rapidly in diameter and
become greatly convoluted. The wolffian ducts become densely
pigmented, the miillerian ducts remain an opaque white color.
I n this experiment the form used is one in which the larval
condition persists indefinitely, and although the specimens
used were still larval in form, they were 12 to 14 em. long,
and the ducts and male cloaca were beginning to differentiate.
I n this respect there was much individual variation in a
number of animals killed at hypophysectomy to serve as controls. Some of the females appear in figure 3. The ovaries
themselves differ greatly in size, and there is much variation
in the development of the miillerian ducts (table 1). In the
specimen at the left one ovary has been removed to expose
the ducts, which are slender, straight, unpigmented structures
running along the lateral border of the kidney, inseparable
without magnification. I n others the ducts are sinuous; in
three individuals at the right a high degree of convolution
is already present. These animals are also larger than the
average, and the ovaries are larger, with the pigment spots
that appear with advancing maturity. Attention is called to
the variation displayed, because it will be obvious later that
the retrogressive changes following hypophysectomy vary
HYPOPHYSECTOMY I N SALAMANDERS
337
according to the amount of growth and structural differentiation already present.
Histological conditions in an average control ovary are
shown in figure 14. The ovary is well developed, the larger
ova measuring 350 to 4 0 0 ~in diameter, and no degenerate
follicles are to be found. (Careful examination of all control
ovaries revealed only three or four atretic follicles, all in one
TABLE 1
Controls at time of hgpophysectomy
Male
Cm.
12-14
dim.
11.0 X
11.5 X
8.0 x
8.0 X
dim.
1.25 11.0 X 1.0
.75 16 X 2.0
1.0
8.0 X 1.0
1.0
8.0 X 1.0
Slightly sinuous'
Straight, slender
Straight, slender
'+mieht, slender
Straight, slender Male type
Straight, slender Undeveloped
Straight, slender Undeveloped
?+might. slenderiundevelomd
. -~~
__
Undeveloped
17.0 X 1.0 Straight, slender Convoluted
Undeveloped
13.0 X 2.0 Straight, slender Convoluted
13.0 X 0.5 Straight, slender Slightly sinuous Undeveloped
12-14
12.0 X 0.4 Straight, slender Slightly sinuous Undeveloped
Undeveloped
13.0 X 3.5 Straight, slender /Convoluted
13.0 X 0.5 Straight, slender Straight, thick Undeveloped
13.0 X 0.5 Straight, slender Straight, thick Undeveloped
14.0 X 0.75 Straight, slender Straight, thick Undeveloped
12.0 X 0.5 Straight, slender Slightly sinuous Undeveloped
-~
~ _ _ _ _ _ _ _ _ _ _ ~ ~
~___
-~
_. ~
_______
13.3 X 1.0
.
.
17.0 X
16.0 X
15.0 X
15.0 X
14.0 X
15.0 X
14.0 X
14.5 X
13.0 X
2.5'
3.0'
2.5
2.5'
3.5
2.0
2.5
2.0
2.0
specimen.) The mullerian duct of the specimen figured is
still unconvoluted.
Male controls show the same variability in the size of the
testes (fig. 2), and the wolffian ducts range from the straight,
unpigmented state to a condition of convolution with strong
pigmentation (table 1). Again, these variations are correlated, t o some extent, with the size of the specimen. Histological conditions in a representative male control are shown
in figure 17. The structure is a typical larval testis, the
338
R. K . BURNS, JR., AND ADRIAN BUYSE
lobules lined by one or two layers of spermatogonia. Dividing spermatogonia are common. The stroma is scanty, with
a few well-formed rete tubules. The wolffian duct is of average development (fig. 18), but straight and relatively free
from pigment. The rudimentary inullerian duct is embedded
in its lateral wall.
I n this review of the variable conditions encountered in controls, no reference has been made to adult specimens, which
will be considered later.
TABLE
2
Animals hypophysectomized two months
-
~LENGTH
--
I
GONAD
1
~~
FAT BODY
1 MUIILERIAN DUCT i
WOLFPIAN DUCT
_.
CLOACA
~
Male
12.0
12.0
12.0
- 13.5
__
Average :
13.8
9.0
7.0
6.0
6.0
Convoluted'
Convoluted'
X 1.0 Less than gonad Slightly sinuous'
X 0.7.5
9.0 X 0.5
Straight, slender
x 1.5
9.0 X 0.5
Slightly coiled
X 1.0
6.0 X 1.0
Slightly sinuous
8.0 X 1.1
i
Straight, slender Male type
Straight, slender Male type
Straight, slender Male type
Straight, slender Undeveloped
Straight, slender Undeveloped
/Straight, slender Undeveloped
-I
1
,I
~
- _.
12.6
13.0
13.5
Av;;a~ :
~.
~ 1 6 . 0X 2.75
115.0 x 2.5l
114.0 X 2.0'
1
~
15.0 X 2.5
1-
'
13.0
10.0
16.0
x 2.0
x 1.0
x 3.0
__
Straight, slender ,Slightly sinuous Undeveloped
Undeveloped
Straight, slender ,Convoluted
Tindeveloped
Straight, slender Convoluted
~
-
-~
13.0 X 2.0
-~
4. CONDITIONS I N ANIMALS HYPOPHYSECTOMIZED W H I L E
IMMATURE (HALF-GROWN)
a. Two months after hypophysectomy
I n female hypophysectomized animals, two months after
operation, no significant changes are observable. There has
been no increase in the size of the ovaries (compare tables 1
and 2 ) , but during the same time the whole organism has
likewise failed to grow. This is probably due to the fact
HYPOPHYSECTOMY IN SALAMANDER.S
339
that a great part of the intervening period was required for
recovery from operative injury and interruption of feeding.
The ovaries of this group are little altered from the condition
shown in figure 14, but two of the three specimens show atretic
follicles in considerable numbers.
There is also little change in the males of this group. The
testes are larval in form, and do not show material variation
from the control group in figure 2. The wolffian ducts of two
are convoluted and pigmented, but this is not the case in the
TABLE 3
Animals kypophysectontized four months
~
Om.
______
____
Average :
14.3
13.3 X 1.0
13.7
14.8
~.
_-
6.0 Straight, slender Straight, slender Undeveloped
3.5 Slightly sinuous' Straight, slender Undeveloped
3.5 Straight, slender Straight, slender Undeveloped
_________
~
19.0 X 4.3
I
17.0 X 2.5 1 20.0 X 4.0 Straight, slender Slightly sinuous Undeveloped
11.0 X 2.5
28.0 X 4.5 Straight, slender Slightly sinuous IUndevrloped
_ _ _ _ _ ~ ~
_
I
~
Average :
b. Arzimals studied f o u r morzths after hypophysectomy
Two females and three males, studied four months after
operation, show effects attributable to hypophysectomy. During this interim there was recovery from the effects of operation, with resumption of growth, and these animals have an
average length above the maximum for the group at the time
of operation (table 3). In spite of this, the gonads and ducts
340
R. K. BURNS, JR., AND ADRIAN BUYSE
remain quite undeveloped in animals at least one year of age.
The two females studied have ovaries of very different size.
The larger set are just the size of the largest control ovary
at the time of hypophysectomy, four months before; but the
oviducts of this animal are straight and slender. The ovaries
of the other female are very small, smaller than any control
specimen, and the oviducts quite undeveloped. Appearances
suggest cessation of development after operation. Histologically, these ovaries present much the same picture as at
two months. The general appearance of the ovary is good,
but atretic follicles are common.
The males of this group (table 3 ) have extremely slender,
undeveloped testes which are thin and leaf-like, with a peculiar transparency. They are somewhat longer than those
of the control group, but in width and thickness (dimensions
in which maturing testes ordinarily increase enormously)
these testes are actually smaller than the controls. One is
shown in figure 19, for contrast with the normal immature
testis of figure 17. The testis lobules are shrunken and
collapsed, the stroma is disorganized and largely composed of
a non-staining connective tissue, of mucoid type.
General conditions in animals hypophysectomized four
months suggest a sex difference in the response of the gonad
t o the deficiency. I n the ovary there is inhibition of further
development, but degenerative changes are not marked,
except for a follicular atresia which has not yet become
quantitatively serious. I n the testis marked degeneration has
occurred histologically, with reduction in size and macroscopic change of appearance.
c. A n i m a l s studied six m o n t h s a f t e r hypophysectomy
Members of a group studied six months after hypophysectomy had grown from approximately 14 cm. to lengths
varying from 18 to 20 em. (table 4). Nevertheless, there are
no indications of further development in the reproductive
system.
341
HYPOPHYSECTOMY IN SALAMANDERS
Two of the three females of this group are shown in figure
5. The ovaries are not significantly larger than those of the
larger controls at hypophysectomy (fig. 3 ) . They are immature in appearance, with no traces of pigmentation. The
oviducts are of about the same diameter as the larger control
oviducts ; however, they are unconvoluted and but slightly
sinuous. The condition suggests failure to develop, rather
than retrogression from a condition of convolution. Histological examination of the ovaries reveals degenerative
TABLE 4
Animals hypophysectomized six months
Male
Cm
.
18.5
20.0
,
Mm.
17.0 X 1.0
14.0 X 1.0
dim.
1
34.0 X 4.0 Slightly sinuous' Slender
28.0 X 5.0
sinuous' Slender
Undeveloped
Undeveloped
~~~
Average :
I
Female
20.6
20.2
19.0
:
Av;:y
~
i
20.0 X 3.0 23.0 X 6.5 Small, slender
20.0 X 2.5 34.0 X 7.0 Small, slender
17.0 X 2.5- 34.0 X 5.0 Small,~slender
_ _ _ _
19.0 X 2.7
~~
~~
31.0 X 6.1
~
~
~
_
~
_
_
_
_
~~~~
~
~
changes (fig. 15). Follicles in various stages of resorption
occur. Arrows indicate a follicle in an early stage of resorption and several corpora atretica. The latter are very
numerous in the ovaries of this group. The largest follicles
are still no larger than those of the control ovaries at
hypophysectomy (350 to 400 p).
The two males of this group are shown in figure 4,and, like
the preceding group, the gonads show slight increase in length
but a decrease in other dimensions. They are extremely
slender and translucent in appearance. The sections show
degenerative changes like those pictured in figure 19.
~
~
~
~
342
R. K. B U R N S , JR., A N D ADRIAN BUYSE
d. A n i m a l s studied tern morzths a f t e r hypophysectomy
This group comprised two females and two males, approximately 20 em. in length. The gonads and ducts are quite
similar in size to those pictured in figures 4 and 5 . The
ovaries are noticeably shrunken, and degeneration is evidently more advanced than at six months. A typical section
appears in figure 16. There are fewer well-developed ovocytes, and greater evidences of deterioration in the form of
atretic follicles and corpora atretica, many of the latter being
in advanced stages and heavily pigmented.
The two males are quite similar histologically. A representative section appears in figure 20. While the picture is
not normal, and there has been reduction in size, nevertheless
the whole organ presents a better appearance than at four
and six months (compare fig. 19). There are still considerable areas of mucoid stromal tissue, and but little organization in the stroma. The general picture may be said to
indicate a certain recovery, with retention of early larval
character. The wolffian duct is unchanged.
e. A n i m a l s studied oNe year a f t e r hypophysectomy
One female and one male were kept a full twelve months
after hypophysectomy. This pair were among the largest at
hypophysectomy (14 em.), and the male was identified as
such at the time, because of definite enlargement of the cloaca.
It may be assumed that this pair represented the maximum
development of the reproductive organs attained at the time
of hypophysectomy. One year later a length of 20 em. for
the female, and 21 em. for the male, had been attained. The
reproductive systems, however, reveal the same arrested
development encountered hitherto.
The ovaries, ducts, and fat bodies of the female specimen
are shown in figure 6, for comparison with a control female
of the same age in figure 7. This control animal was one upon
which hypophysectomy had been attempted, but because of
hemorrhage and other difficulties, the hypophysis was not all
HYPOPHYSECTOMY I N SALAMANDERS
343
removed. The animal did not change color, and when studied
at the end of a year was 20 em. long. (The only effect of the
abortive operation is seen in the enlargement of the fat
bodies, probably as a consequence of operative injury. Fragments of anterior lobe and heterogeneous tissues were
recovered from the operative site.) The ovaries of the experimental animal are typically small and shrunken. Numerous pigment patches indicate much follicular atresia. When
compared with the large ovaries and huge pigmented ova of
the control specimen, no remarks are necessary. The sections of these ovaries are similar to that of the ten-months
ovary shown in figure 16, and are not pictured. A photograph
of a small part of the control ovary of figure 7 is shown in
figure 24, for comparison.
The oviducts are moderately developed and convoluted, but
not more so than in other specimens already discussed. The
development is small when compared with the huge oviducts
of the control specimen, the coils of which ( 0 ) appear at the
sides of the ovaries and fat bodies in figure 7. The conclusion
arrived at in previous cases seems justified: that the oviducts
have merely retained, to an extent at least, the development
present at hypophysectomy.
The reproductive organs of the male are shown in figure 8.
The testes are the largest found in an hypophysectomized
animal of any age; yet, while a little larger than any control
specimen at hypophysectomy, they a r e still rudimentary when
compared with those of a control male of the same age and
size (fig. 9). The wolffian duct or vas deferens is convoluted,
but it is also very small when compared with the thick coils
of the control duct.
A typical section from the larger testis appears in figure 21.
Despite its greater size, the organ is still larval in type. There
are present, however, pigment patches in the stromal tissue,
particularly in the hilar region, such as are found in older
specimens. This may indicate retrogression from a more
advanced condition. The huge testes of the control animal
of figure 9 (T)were filled with ripe spermatozoa (fig. 25).
344
R.
rc.
BURNS, JR.,
AND ADRIAN BUYSE
5. CONDITIONS IN ADULTS, AFTER HYPOPHYSECTOMY
Four adult animals, two females and two males, 22 em. in
length, were operated on along with the immature group.
Inasmuch as the hypophysectomy was done in March, they
should have possessed mature reproductive organs. The
males had typically developed cloacae, with prominent rugae
and the usual pigmentation.
Eight months after hypophysectomy, the gonads of these
animals were degenerated to a greater extent than in any
immature animal. The gonads and ducts of the females are
shown in figures 10 and 11. I n each the fat body has been
removed on the right to expose the ovary. I n one, the ovary
(fig. 11)is darkly pigmented and largely composed of corpora
atretica. Close examination (fig. 26) shows that the largest
intact ova are less than one-third the diameter of the large,
yolk-laden ova of the control adult ovary of figure 24. The
degeneration that has occurred is indicated by the masses of
corpora atretica which compose most of the ovary. The other
ovary (fig. 10) is of a peculiar yellowish color, approaching
white. It has reverted almost to the undeveloped condition
seen in the arrested ovaries of the young group. The oviducts of these females show simple coils, flattened against
the dorsal body wall, as in the half-developed normal specimens of figure 3. They are larger than these, chiefly because
they belong to much larger animals. Their lack of development is better realized by comparison with the full, thick coils
of the oviduct in figure 7.
One of the males of this group is shown in figure 12. The
extremely reduced testis is seen on the left (indicated by
arrow), where the fat body has been removed. It is irregular
in form and much shrunken. The amount of degeneration
is seen by comparison with the testes of a control male of
the same size, shown in figure 9. The relative development
of the wolffian ducts is evident from the same pictures.
But it is only after histological study that the extreme degeneration of these testes can be fully realized. Figure 22
shows a typical section from the testis of figure 12, and a
WYPOPHYSECTOMY I N SALAMANDERS
345
loop of the wolffian duct appears in figure 23. No further
description is necessary. The companion male was similar to
this one, in all respects. The control testes of figure 9 were
mature organs, containing ripe spermatozoa (fig.25).
6. T H E RESPONSE O F T H E MALE CLOACA TO HYPOPHYSECTOMY
The reaction of the ducts to hypophysectomy has been taken
up, but no reference has been made to the male cloaca, except
to describe its development in the normal male. Out of
eighteen immature males used for operation or sacrificed as
controls, five could be identified by the cloaca. The others
were only identified as males at autopsy. Two males of the
latter class appear in figure 4, six months after hypophysectomy. These animals were 16 cm. long at autopsy, and
would normally have shown typical male cloacae. The failure
of cloacal development is explained by the atrophic condition
of the testes. These cases are typical of all males in which
the cloaca was as yet undeveloped at hypophysectomy. On
the other hand, among the experimental males were four
immature animals in which development of the cloaca had
already occurred and two adults. I n all these cases retrogression followed. It may be pointed out that among the specimens hypophysectomized while immature, the only cases in
which convolution of the wolffian ducts still existed after a
lapse of time were those which showed cloacal developmeni
a t hypophysect omy.
An illustration of retrogression of the cloaca in an adult
male eight months after operation is seen in figure 13. The
organ, ordinarily large, turgid, and darkly pigmented, is
small, shrunken, and almost entirely lacking in pigment.
7. T H E F A T BODIES I N HYPOPHYSECTOMIZED ANIMALS
The hypertrophy of the fat body is apparently without
relation to sex, and has been described by others, recently
by Woronzowa and Blacher ( '30). It also occurs irrespective
of the relative maturity of the specimen at hypophysectomy.
I n the immature group, from a variable status in control
346
R. K . B U R N S , JR., A N D A D R I A N BUYSE
specimens at hypophysectomy (figs. 2 and 3), the fat bodies
( F ) have become uniformly much larger than the gonads at
the end of six months (figs. 4 and 5). After a year, when the
animals are of adult size, the fat bodies show enormous
superiority over the gonads (figs. 6 and 8) when compared
with a normal adult (fig. 9). The anomalous condition of the
f a t body in figwre 7 has been explained in section 4 (e).
8. COMMENT
The results described agree very well with those of Woronzowa and Blacher ( ' 3 0 ) , who carried out a similar experiment
on a mixed group of adult and young European forms. The
largest group in their experiment consisted of European
axolotls, the transplanted Amblystoma mexicanum-a
relative of the form used here. Their material of the species
named consisted of nine individuals hypophysectomized while
young and ten adults. The immature specimens were examined from six to sixteen months after opelation. Their
results, briefly given, are like our own, but the progress of
the retrogressive changes is not followed closely. Follicular
atresia is not described. It is stated that females are less
inhibited than males. Observations on ten adult specimens
are extended t o three years, much longer than our own experiment-which probably accounts for the greater degeneration
observed in accessory structures.
Woronzowa and Blacher also describe hypertrophy of the
fat body, with cases even more extreme. Two hypotheses may
be advanced to account for the enormous storage of fat in
the fat body. The inhibited condition of the gonads may
result in the conversion and accumulation of the materials
ordinarily utilized by them. The normal correlation between
size of fat body and the period of reproductive activity supports this idea. On the other hand, it is quite likely that
hypophysectomy may radically alter metabolism, leading to
storage of fat. In this case the fat body, as an organ
especially adapted to this rBle, would probably accumulate the
larger share.
HYPOPEYSECTOMY IN SALAMANDERS
347
The variability of the ducts in hypophysectomized animals
of fairly uniform size at operation was puzzling until it was
observed that variations, within about the same limits, existed
in the control group. It was then apparent that the condition of the ducts after hypophysectomy depends largely upon
the amount of differentiation existing at operation ; in other
words, ducts undifferentiated at hypophysectomy remain so,
but when well established differentiation already exists, this
condition is largely retained during the first year. This is
also true of the male cloaca. Probably in a longer period of
time, more definite degeneration would occur in these structures, as the more extended observations of Woronzowa and
Blacher on adults show. Our own findings are probably to be
expected, if changes in accessory structures are regarded as
definitely secondary to retrogression of the gonads.
The process of resorption in atretic follicles is interesting,
and from the standpoint of cytology, rather spectacular.
However, it is probably not entirely specific in type. Stieve
(’21) has found that various unfavorable factors in the
environment of maturing female Tritons may cause f ollicular
atresia, and although the process is not described histologically, some figures suggest a similarity to the process observed here. I n later stages of atresia there are close resemblances between corpora atretica and the corpora lutea that
follow ovulation. However, the degenerating follicles here
encountered involve young ovocytes (350 p ) and not maturing ova as in Stieve’s material. I n view of the sensitivity of
the ovary to unfavorable influences, it may be that hypophysectomy is merely another unfavorable condition (of the
internal environment) t o which the ovary responds by follicular atresia.
9. SUMMARY
I n specimens of Amblystoma tigrinum Green (‘axolotl’
variety), hypophysectomized while immature, there are degenerative changes in the gonads of both sexes. Follicular
atresia occurs in the ovary and there is marked histological
348
R. K . BURNS, JR., A N D ADRIAN BUYSE
disorganization in the testis. These effects occur in spite of
the fact that the subjects eventually attain adult size. Later
there appears to be a measure of recovery in the testis, with
retention of larval form. Apparently males are affected
sooner than females and more severely, which is in conformity
with results following administration of anterior hypophysis
in which males show the greater response. Although follicular atresia is still occurring in the ovary at the end of
a year after hypophysectomy, degeneration is not so extreme
as in the testis. The ducts and cloaca remain approximately
in the condition in which they were at hypophysectomy. I n a
few adults hypophysectomized under like conditions, there is
more acute retrogression of the already mature reproductive
organs. I n the testis degeneration is extreme and only
younger ovocytes survive in the ovary. The duct systems
also retrogress, but, within the period covered by the experiment, fail to return completely to a larval condition.
BIBLIOGRAPHY
1914 Metamorphosestudien a n Batrachierlarven.
I. Extirpation
endokriner Driisen. A. Extirpation der Hypophyse. Arch. f. Entwmech. der Organismen, Bd. 39, S. 21-45.
ALLEN, B. M. 1916 Extirpation experiments in Rana pipiens larvae. Science,
N. S., V O ~ . 44, pp. 755-757.
BURNS, R. K., JR. 1930 Effects of hypophyseal hormones upon Amblystoma
larvae, following transplantation or injection, with special ref erence
to the gonads. Proc. SOC.Exp. Biol. and Med., vol. 27, pp. 836-838.
BURNS, R. K., JIL, AND ADRIAN BUYSE 1931 The effects of extracts of the
mammalian hypophysis upon immature salamanders. Anat. Rec.,
vol. 51.
KLATT,B. 1931 Hypophysenextirpation und -Implantation an Tritonlarven.
Arch. f. Entwmech. d. Organismen, Bd. 123.
SMITH,
P. E. 1916 Experimental ablation of the hypophysis in the f r o g embryo.
Science, N. S., vol. 44, pp. 280-282.
1920 The pigmentary, growth, and endocrine disturbances induced
i n the anuran tadpole b y the early ablation of the pars buccalis of
the hypophysis. Amer. Anat. Memoirs, no. 11.
STIEVE,H. 1921 Uber den Einfluss der Umwelt auf der Eierstocke der Tritonen.
Arch. f. Entwmech. d. Organismen, Bd. 49, S. 179-267.
WORONZOWA
UND BLACHER 1930 Die Hypophyse und die Geschlechtsdriise der
Amphibien. I. Der Einfluss der Hypophysenextirpation auf die Geschlechtsdriise bei Urodela. Arch. f . Entwmech. d. Organismen, Bd.
121,
3.
ADLER, L.
s.
PLATES
349
THE A N A T O X I C A L R E C O R D , VOL.
51, NO. 3
PLATE 1
EXPLANATION OF FIGURES
1 Three hypophysectoinizcd animals, several niontlis a f t c r hypopllyseetoitiy, and
control specimen, showing color eliarige and general appearance. X 3.
2 Reproductive organs of a group of immature males, used :is controls a t
hypophysectomy. Note the coiled wolffian ducts of one specimen. F, f a t body.
2.
3 Reproductite organs of a group of irnmatnre females used as controls at
hypophysectomy. The specinieii a t the left has one ovary and f a t body removed
t o expose the ducts, which are slender, straight, and generally undeveloped ;
indicated by arrow. The three individuals a t the right are largcr (14 cm.) and
have convoluted miilleriaii ducts. F, f a t body. X 2.
4 Two male specimens of a group studied six months after liypophysectoiny;
length, 18 em. The testes are extremely thin and slender, the wolffian ducts
straight and undeveloped. The f a t bodies (P)are enlarged. X 2.
5 Two female specimens of a group studied six months after hypophysectoiny;
length, 18 em. The ovaries show no greater development than the larger controls,
although the whole organism has increased greatly in size. The mullerian ducts
a r e fairly thick, but uncoiivoluted. The f a t bodics ( P ) are enlarged. x 2.
x
350
HYPOPHYSECTOMY 1N SALAMANDERS
PLATE 1
B. R. BURNS, J B . , AND ADRIAN BUYSB
351
PLATE 2
EXPLANATION OF FIGURES
G Reproductive organs of a fernale studied one year after hypopllysectomy;
length, 20 em. The ovaries are small and shrunken in appearance, the oviducts
show approximately the same condition as the larger control oviducts at hypophysectomy. The f a t bodies (F)are enormous. X 2.
7 Reproductive organs of a control female of the same age and size as
the experimental animal of figure 6. F, f a t body (see t e x t ) ; 0,coils of oviduct.
x 2.
8 Reproductive organs of a male studied one year after hypophysectorny;
length, 21 em. The testes a r e somewliat larger than the controls at hypophysectoiny, but relatively undeveloped. The wolffiau ducts are like those of the
better developed controls. P, f a t body. X 2.
9 Reproductive organs of a control male of the same age and size as the
experimental animal of figure 8. The testes are large and pigmented, and were
filled with ripe spermatozoa and recently emptied lobules. F, f a t body; T,testis.
x 2.
10 Reproductive organs of a n adult female, liypophysectoinized eight months
previously. The f a t body ( F ) has been removed on the right t o expose the
degcnerate ovary. Compare figure 7 . X 2.
11 Reproductive organs of another hypophysectoinized female adult, eight
months a f t e r operation. The degeneration of the ovary is less extreme than in
the preceding case, b u t very great when compared with figure 7 . X 2.
1 2 Reproductive organs of a n adult male hypophysectomized eight months
previously. The f a t body has becn removed on the left side to expose the very
degenerate testis, indicated by arrow. The wolffian ducts are slender, but con
voluted. Compare figure 9. X 2.
13 Cloaca of the hypophysectomized adult male of fignre 12. It is shrunken
and almost without pigment. X 2.
352
PLATE 2
HYPOPHYSECTOXY I N SALAMANDERS
K. X. BURNS, JK., AND ADRIAN BUYSE
353
PLATE 3
EXPLANATION OF FIGURES
14 Rrpresentative ovary from a group of female controls at hypophyseetoniy.
The largest ovocytes range from 350 t o 400 p in diameter. No atretic follicles
or corpora atretica are present. The miillerian duct is slender and unconvoluted.
X 30.
15 Section from one of the ovaries shown in figure 5, six months a f t e r hypophysectomy. The larger follicles show no inrrease in size, and are fewer in number.
Resorbing follicles are common (first arrow on left), and many early corpora
atretica are present. The oviduct is thickened, b u t not convoluted (fig. 5). X 30.
16 Section of an ovary ten inoiiths after hypophysectomy. The larger follicles
still show no material increase in size. Resorbing follicles and corpora atretica
in all stages arc common. X 30.
354
HYPOPHYSECTOMY IN SALAMANDERS
PLATE 3
R. X. BURNS, J R . , AND ADRIAN BUYSE
355
PLATE 4
EXPLANATION OF FIGURES
17 Representative testis of a control male at hypophysectomy; a typical larval
testis. x 90.
18 Wolffian duct of the specimen whose testis appears in figure 17. The
rudimentary miillerian duct lies embedded in the distal wall. x 90.
19 Degenerate testis of a male four months after hypophysectomy. Note the
disorganized condition of the testis lobules and the mucoid degeneration in the
stroma. X 90.
20 Testis of a male ten months after hypophysectomy. There has been some
recovery from the condition pictured in figure 19, but evidences of deterioration
are still obvious. The wolffian duct appears below. X 90.
21 Section of a testis from the specimen in figure 8, one year after hypophysectomy. The lobules are still larval i n character, although this animal was of
adult size. x 90.
22 The greatly degenerated testis of a n adult male, eight months after
hypophysectorny. The mucoid degeneration seen in immature testes is more
extreme in adults. X 90.
23 Wolffian duct of the adult male, the testis of which appears in figure 22.
x 90.
356
HYPOPHYSECTOMY IN SALANANDERS
PLATE 4
R. X. BURNS, JR., AND ADRIAN BUYSE
35i
PLATE 5
EXPLANATION OF FIGURES
24 A small portion of an ovary of the adult control specimen of figure 7.
This photograph is on the same scale as figures 15 and 16. X 30.
25 A small portion of one of the control testes of figure 9, showing the
masses of spermatozoa which filled most of the organ. The part shown represents about one-tenth of the entire cross-section. X 200.
26 Photograph of a section through the ovary shown in figure 11. The
surviving cells are limited to young ovocyte stages. The heavily pigmented
masses which compose most of the substance of the ovary are the corpora atretica
resulting from the resorption of mature or well-developed ova. The amount of
pigmentation in corpora atretica is apparently in proportion to the yolk content
of the resorbed egg. Compare figures 13 and 16, where much younger and
smaller cclls are involved. X 30.
358
HYPOPHYSECTORIY I N SALAMANDERS
PLATE 8
R. K. B U R N S , J R . , AND ADRIAN BUYSE
359
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