close

Вход

Забыли?

вход по аккаунту

?

Neo-ovogenesis in the adult monkey. Consequences of atresia of ovocytes

код для вставкиСкачать
NEO-OVOGENESIS I N THE ADULT MONKEY
CONSEQUENCES O F ATRESIA O F OVOCYTES
GERTRUDE J. VERMANDE-VAN ECE '
Department of Anatomy, Y a l e University School of Hedicine
New Hrven, Connecticut
T W O FIGURES
New ova form from the germinal epithelium in some small
adult mammals (Allen, '23 ; Cowperthwaite, '25 ; Evans and
Swezy, '31 ; Allen and Creadick, '37; Schmidt and Hoffman,
'41; Latta and Pedersen, '44). From the time of Waldeyer,
1870, it has been accepted that the human ovary contained at
birth all the ovocytes for the future life. Waldeyer's estimate
was 36,000-50,000 in the neonatal ovary. Von Hanseniann
('12)? counted every fifth section ,of a neonatal ovary and
estimated the total number between 40,000 and 80,000. Hammar and Hellmann ( '20), counted the ovocytes in a girl 3 years
and 8 months old who died of thyreoaplasia and found 194,283
ovocytes in one ovary. Haggstrom ('2l), counted the ovocytes
in a young woman of 22 years and found 419,911 ovocytes in
the two ovaries. From these counts the number of 400,OO ovocytes with which the young girl is born has been generally
accepted. This theory of Waldeyer that no new ova are
formed during postnatal life implies a possible life of the
ovocytes of 45-50 years.
More recently the formation of new ova throughout sexual
maturity, as in the lower mammals, has been assumed (Evans
and Swezy, '31 ; Simkins, '32 ; Schwarz and coworkers, '49).
Ovogenesis may be either continuous or in waves related to
ovulation, and may occur from the germinal epithelium or from
a neogenic zone in the cortex of the ovary; the rate of formation may diminish progressively with age.
'This study was supported by a grant from the United States Public Health
Service.
207
208
GERTRUDE J. VERMANDE-VAN ECK
The follicle can degenerate at any stage of development.
Atresia is assumed to be of short duration for the primordial
and small primary follicles; the follicle is resorbed and its
space in the ovary replaced with stroma. The zona pellucida
from the growing follicle may persist for some time after disintegration of the ovocyte and follicle cells. The process of
atresia of the growing follicle has never been ascertained.
Atresia of the mature follicle was estimated by Sturgis ('49),
to be complete after about 5 weeks; the corpus atreticum can
then remain for months in the ovary.
In the human, one follicle usually reaches maturity each
month; all other larger follicles most likely degenerate (Allen
and coworkers, '30). This suggests that atresia occurs in
waves, at least as far as the large follicles are concerned.
Evans and Swezy ( '31), described such waves in relation to
the ovulatory cycle ; they mentioned very intensive atresia in
the rat, guinea pig, cat and dog, and accepted formation of
ova from the germinal epithelium in corresponding waves.
Mandl and Zuckerman ( '49) could not confirm this hypothesis
after counting the normal and atretic ovocytes in rats' ovaries.
At early diestrus the number of normal ova was at a maximum,
and at late diestrus at a minimum, whereas the other phases
of the cycle did not show significant differences. These slight
changes during the estrous cycle were negligible compared to
changes in age and litter relationship. The number of ovocytes in the rat decreased with advancing age (Arai, '20;
Mandl and Zuckerman, '50).
Green and Zuckerman ('50) were the first to estimate the
number of ovocytes of the ovaries of rhesus monkeys. The
ovarian follicles of 13 monkeys were divided into 7 groups,
representing different stages of development. I n each group
both the normal and the atretic follicles were counted. Their
analysis did not support the viewpoint of Evans and Swezy
('31) that the total number of ovocytes of the rhesus monkey
fluctuates in phase with the menstrual cycle, and that its maximum coincides with ovulation. Only the number of larger
follicles is at its peak at this time. These findings are similar
NEO-OVOGENESIS I N THE ADULT MONKEY
209
to the results obtained by Mandl and Zuckerman ('50) in the
rat.
Ovogenesis in the adult mammal has been studied by different methods. Early investigators used the histological
techniques : Winiwarter and Sainmont ( '08) in the cat ; Allen
( '23) in the rat; Cowperthwaite ( '25) in the rat; Evans and
Swezy ( '31) in the dog, cat, guinea pig, monkey and human;
and Simkins ( '32) in human ovaries.
Experimental methods were used later. Allen and Creadick
('37) used the colchicine technique to arrest mitosis in the
germinal epithelium of the rat. Schmidt and Hoffmann ( '41)
did Simkins experiments with guinea pigs. Latta and Pedersen ('44) used India ink to mark the germinal epithelium of
the rat in vivo. Jones ('49) also used India ink f o r vital staining of the germinal epithelium of the rat. Mandl and Zuckerman ( '50) used unilateral castration of the rat and destruction
of the germinal epithelium by tannic acid and carbolic acid.
Simpson and van Wagenen ('53) studied the ovaries of immature monkeys that had received high doses of follicle stimulating hormone. These experiments were contradictory or
were interpreted differently. Schwarz and coworkers ( '49)
concluded that between 20 and 40 years of age ova are formed
from the germinal epithelium of human ovaries. The number
of ova diminished rapidly at the onset of the climacterium and
in the menopause only a few or no ova were present.
The purpose of this paper is t o approach this problem from
another point of view. The number of normal and atretic ovocytes in rhesus monkeys were estimated, giving special attention to the two possible mechanisms for the diminishing
number of ovocytes; that is atresia alone or the atresia in
combination with a decreased neogenesis.
MATERIALS AND METHODS
The ovaries were obtained from several sources.
1. Eight ovaries of immature monkeys from our own colony
(Yale Series).
210
2.
GERTRUDE J. VERMANDE-VAN ECK
Six ovaries of immature monkeys from the Carnegie
Colony (Carnegie Series C l ) .
3. Seven ovaries of mature monkeys from the Carnegie
Colony (Carnegie Series C2).
The ovaries of the Yale Series were fixed in Bouin's solution, embedded in paraffin, cut at 8 p and stained with hematoxylin and triosin. The ovocytes, normal and atretic, were
counted at all stages of development. For this purpose we
used the technique described by Green and Zuckerman ( '50).
The follicles were classified in 7 groups in order to promote
uniformity in publications and to enable us to compare our
figures with theirs.
The classification is as follows:
1. Primordial ova with complete cover of flattened cells or
incomplete epithelial cover.
2. Ova completely surrounded by 1 layer of cuboidal cells.
3. Ova completely surrounded by 2 layers of cuboidal cells.
4. Ova completely surrounded by 3 layers of cuboidal cells.
5. Ova completely surrounded by 4 or 5 layers of cuboidal
cells.
6. Ova completely surrounded by 6 or more layers of cuboidal
cells.
7. Follicles with antra.
The primordial ovocytes and the ovocytes in the small follicles were counted in every 40th section. F o r the large growing follicles (group 6) and the follicles with antra, every
section was screened.
Oocytes were counted only when the nucleolus was visible.
The numbers of ova in follicles counted in groups 1-5 were
multiplied by 40 and by a correction factor for the thickness
of the section. The numbers of groups 6 and 7 were multiplied
only by the correction factor. Abercrombie ('46) has shown
that when the diameter of the object counted, e.g. the nucleus of a cell, is large in relation to the thickness of the section, the true nuclear population P will be approximately:
section thickness
diameter.
section thickness + nuclear diameter x
211
NEO-OVOGENESIS I N T H E ADULT MONKEY
The average size of the nucleoli of the different groups and
the corresponding correction factors for 10 p section thickness
were determined by Green and Zuckerman ( '50). We repeated
the measurements on our ovaries, which were fixed the same
way. The average of 20 follicles of group 1 differed less than
3% from the figures given by Green and Zuckerman. The correction factor for 8 ~-r section thickness was applied to our
series (table 1).
TABLE 1
Average size of nucleoli of group 1-7 follicles, and the correspondhg correction
factor for sections of 8 and l o p thickness
QROUP
NUCLEOLAR SIZE
IN MICRONS
CORRECTIOON
FACTOR
CORREOTION
PACTOR
10 B
Bfi
0.79
0.77
0.76
0.73
0.71
0.69
0.66
0.74
0.73
0.72
2.7
3.0
3.1
3.6
4.1
4.6
5.8
0.69
0.66
0.63
0.58
Figures from Green and Zuekerman.
Duplicate counts were made from 5 ovaries. The counting
error was lower than 876, and was mainly due to differences
in group 1follicles.
F o r determination of the duration of the atresia, three
monkeys were x-irradiated with 1200 r, divided into two doses
on subsequent days.2 One ovary was removed from each of
two monkeys on day 7, 10, and 14 after irradiation. The
criteria of atresia were : chromatolysis of the nucleus, and
shrinkage, and more intense eosinophilic staining of the cytoplasm of the ovocyte.
RESULTS
1. Yale series
The monkeys of this series had had one or more menstrual
periods but had not yet ovulated. Their weights ranged from
* 200 kilo volts; 15 milli Amperes; 50 em target distance; filter 3 mm Cu
Al; half value layer 1.1 mm Cu.
+ 1m m
212
GERTRUDE J. VERMANDE-VAN E C K
2870-3780gm7 and their estimated ages ranged from two t o
two and one-half years. The total number of ovocytes per
ovary differed widely; the lowest was 22,900 and the highest
117,970, the average number was 50,120 10,600. The total
atresia per ovary was between 2.4 and 6.876, with an average
of 4.5 _t 0.5% (table 2).
TABLE
2
Number of ovocytes in normal monkey ovaries
Yale Series
Immature
animals
MONKEY
NUMBER
TOTAL
OVOCYTES
ATRETIC
OVOCYTES
12R
15R
2OR
74L
75L
95R
103R
103L
22,900
38,110
117,970
40,050
26,630
56,070
53,810
48,130
550
1380
3140
2380
1450
3800
2730
1840
Average
Carnegie Series C1
Immature
animals
201R
201L
202R
202L
209R
209L
Average
Carnegie Series C2
Mature
animals
Average
124R
137R
137L
206R
206L
219R
219L
%J
2.4
3.9
2.7
5.9
5.4
6.8
5.1
3.8
50,120
2140
4.5
2 10,600
r 375
2 0.5
26,480
30,820
124,460
97,520
40,290
45,300
1100
970
4020
3290
2480
1990
4.2
3.1
3.2
3.4
6.1
4.4
60,810
2310
4.1
? 16,470
C 490
5 0.5
76,220
24,030
18,160
58,810
128,930
58,800
58,910
3660
1180
960
1320
5680
4030
3220
4.8
4.9
5.3
2.2
4.4
6.8
5.6
60,550
2960
4.8
2 10,900
& 660
k 0.5
213
NEO-OVOGENESIS IN T H E ADULT MONKEY
The distribution of ovocytes over the different stages of
f ollicular development was relatively constant, and independent of the total number of ova (table 3, fig. 1).
The percentage of atretic ova was constant for each group;
the widest variation occurred in the follicles with antra. The
fact that these monkeys were not selected for periods of the
menstrual cycle may be responsible. The percent of atresia
was low in the primordial ovocytes, and increased gradually
TABLE 3
Distribution of ovocytes according to the size of the follicle expressed
in percentage of total ovocytes
Yale Series
Immature
rhesus monkey
12R
15R
20R
74L
75L
95R
103R
103L
Average
Carnegie Series C1
Immature
rhesus monkey
201R
201L
202R
202L
209R
209L
Average
Carnegie Series C2
Adult
rhesus monkey
Average
124R
137R
137L
206R
206L
219R
219L
93.7
84.7
91.0
82.3
91.0
89.4
89.9
90.2
4.8
9.3
7.8
10.6
5.7
5.8
6.8
7.5
1.1
5.6
1.1
6.8
3.2
4.6
3.3
2.2
.16
.23
.02
.06
.07
.06
.02
.03
.10
.23
.06
.21
.06
.04
.04
89.0
7.3
3.5
.08
.10
77.3
74.2
84.9
83.0
67.4
62.1
14.9
17.2
11.2
12.2
17.9
23.0
7.2
8.3
3.8
5.6
14.4
14.5
.11
.17
.04
.05
.05
.09
.37
.34
.04
.07
.19
.25
74.8
16.1
9.0
.08
.21
83.8
82.6
80.2
87.6
93.3
76.0
83.2
12.7
12.2
13.4
8.2
3.8
13.9
10.0
3.4
5.0
5.7
4.0
3.4
9.7
6.6
.02
.08
.09
.06
.07
.13
.12
.11
.17
.23
.06
.06
.18
.19
83.8
10.6
5.4
.08
.14
.lo
214
GERTRUDE J. VERMANDE-VAN ECK
during the process of maturation t o attain an average of
38 3.576 in the follicles with antra. Since both ovaries of
the same monkey were studied in only one instance, the number of ovocytes in the right and left ovaries of this group
could not be compared (table 4,fig. 2).
100
80
0 Y a l e series
0 Garnegie I
0 Cornegie 2
-
In
al
e
h
>
60 -
0
0
c
0
c
u-
40-
8
20 -
Groups
I
2
3 -5
6
7
Fig. 1 Uistribut,ion of ovocytes of the rhesus monkey according to the size of
follicle.
2. CarNegie series C l
The monkeys of this group were ovariectomized 6 weeks
after joining the colony. All had shown one o r more menstrual
periods, and the day of cycle at which the ovaries were removed was known. The ovaries contained small and medium
sized follicles with antra, but showed no signs of ovulation.
The average total number of ovocytes was 60,810 16,470,
with an average atresia of 4.1 2 0.5% (table 2).
215
NEO-OVOGENESIS I N THE ADULT MONKEY
The distribution of follicles of different size among the
different groups was constant (table 3, fig. 1) as was the percentage of atresia per group (table 4,fig. 2). The total number of ovocytes varied widely from one monkey to the other.
The right and left ovaries of the same monkey contained
nearly equal numbers of ovocytes.
TABLE 4
Percentages of atretic ova in normal monkey ovaries
MONKEY
NUMBER
Yale Series:
Immature
rhesus
monkeys
12R
15R
20R
74L
75L
95R
103R
103L
DAY OIP
O Y O ~ E GROUP 1
25
19
19
55
58
61
..
.
.
Average
Carnegie
Series C l :
Immature
rhesus
monkeys
201R
20111
202R
202L
209R
209L
23
23
12
12
18
18
Average
Carnegie
Series C2:
Adult
rhesus
monkeys
Average
124R
137R
137L
206R
20GL
219R
219L
..
57
57
23
23
22
22
1.4
2.9
1.2
5.9
5.4
6.8
4.9
3.8
GROUP 2
13.5
5.6
12.5
13.7
11.2
12.5
6.3
4.1
Gs:
GROUP 6
23.1
9.4
4.6
11.7
7.1
7.8
6.8
5.8
4.0
9.8
9.5
rt .7
-C 1.4
k 2.1
4.0
2.7
2.5
3.0
3.4
3.2
6.3
4.7
8.8
2.6
5.3
7.3
3.8
2.5
8.9
7.5
16.5
68
9
14
17
21
11
12
19
3.1
5.8
6.5
zk .9
& 2.5
3.3
4.0
3.5
2.0
3.8
5.6
5.3
10.8
7.5
9.0
5.4
9.9
11.6
5.5
17.4
12.5
14.6
...
13.2
8.5
8.1
3.9
f .5
8.5
10.6
t .9
& 2.1
42
28
39
31
50
27
53
32
21
38
t 6.8
t 3.5
27
9
4
26
21
24
26
23
30
27
25
34
..
k .2
GROUP 7
18
22
rt 4.0
t 2.9
40
10
19
20
34
42
12
38
39
32
27
20
48
34
25
41
rt 5.0
-C 4.4
Dated from the time of onset of the preceding vaginal bleeding.
216
GERTRUDE J. VERMANDE-VAN E C K
3.
Carszegie series C2
The monkeys of this group, with the exception of M206,
were observed during longer periods in the colony. They had
had several menstrual periods which were regular, but with
greater intervals during the summer. The average total num100
PJ
Yale series
0 Cornegie I
8 Cornegie 2
80
'
o 60
2
L
b
Groups
I
2
3-5
6
7
Fig. 2 The percentages of atretic ova in the rhesus monkey. Distribution over
groups according t o size of follicle.
ber of ovocytes was 60,550 t 10,900, the average atresia of
4.8 f 0.5%. Again the number of ovocytes differed from animal to animal. The numbers of ova in the right and left
ovaries were similar with the exception of monkey 206 (table
2 ) . Distribution over the groups was not different from the
other series of monkeys (table 3, fig. 1). The days of the cycle
on which the ovaries were removed are marked in table 4;the
217
NEO-OVOGENESIS I N T H E ADULT MONKEY
presence of one or more corpora lutea in the ovaries indicated
that these animals had reached full maturity.
Duratiolz of the atresia. The duration of the atresia of the
follicles was determined by x-irradiation of the ovary with
doses adequate to destroy the growing follicles. Three young
adult monkeys, weighing 36504200 gm, two and one-half to
three years of age received calculated tissue doses of 1200 r
TABLE
5
Normal and atretic ova in x-rayed monkeys 7-14 days after 12OOr
MONKEY
NUYBPR
TOTAL OVA
ATRETIC OVA
%
'
ATRPSIA
~
87R
92L
98R
98L
Average
69,750
50,420
77,880
77,520
3,340
3,830
5,760
4,820
4.8
7.6
7.4
6.2
68,890
4,440
6.5
TABLE 6
Per cent atresia in x-rayed monkeys 7-14 days after 1300r
MONKEY
NUMBER
DAY 03"
CYCLE
87R
92L
98R
98L
19
19
22
22
Average
GROUP 2
DAYS
3.6
5.0
6.4
5.8
58
45
59
79
7
10
10
14
5.2
60
GROUP
1
(600 r on two successive days) between the 19th and 22nd day
of the menstrual cycles. They were irradiated through portals
of 10cm2 over the ovarian area. They were ovariectomized
after 7 , 10, and 14 days. The irradiated ovaries had no follicles larger than group 2. All growing and mature follicles
were transformed into corpora atretica. Only in the ovaries
removed 7 days after irradiation, and in one ovary removed
10 days after the irradiation, a few atretic ova, which had derived from secondary follicles, were still recognizable.
218
GERTRUDE J. VERMANDE-VAN ECK
After 14 days no ova surrounded with more than one layer
of cells were present, and the atresia of all other follicles was
complete. Four of these ovaries were suitable for counting
(table 5).
The total number of ovocytes was relatively high (av. 68,890,
with an atresia of 6.5%). It was remarkable that the atresia
in the primordial ovocytes was not higher than in the normal
ovary, whereas the atresia of follicles in group 2 averaged 60%
(table 6).
DISCUSSION
The number of ovocytes differed greatly in individual monkeys; even monkeys belonging to the same age group showed
these differences. Mandl and Zuckerman ('50) found f o r rats
that litter relationship and age were associated with significant differences in the number of ovocytes. Rats from the
same litter did not differ much, whereas rats of different
litters did. I n addition, they found, in agreement with Arai
( '20), that the number of ovocytes decreased with age.
I n our experiments nothing was known about the relationship of the monkeys used, as all were imported from India.
For the Yale series the estimates of age were based upon
stage of dentition and body weight (van Wagenen), as well as
onset of menstrual periods, and the continuing dnovulatory
cycles. I n the Carnegie series the age was unknown; the immature monkeys had not ovulated and had shown only one
menstrual period ; the mature group had shown regular menstrual periods and had corpora lutea in their ovaries. The
mature monkeys, as a group, had the same average total number of ovocytes as the immature monkeys. The number of ova
in 13 adult monkeys averaged 55,500 for the right ovaries,
and 53,800 for the left (Green and Zuckerman). The total
number of ovocytes of the different groups was: 90% primordial or primary follicles with one layer of cells around them
(group 1 and 2) ; the number of larger follicles decreased inversely and exponentially with the size. The atresia from the
ovocytes with two or more layers alone was 4.6 5.1% of the
total number. This does not include the atretic ova with one
NEO-OVOGENESIS I N THE ADULT MONKEY
219
layer of cells around them, so the percentage was actually
higher.
Sturgis ('49) divided the atretic follicles into three stages.
I n the first stage, the disorganization and breakdown of the
granulosa layer occurs, the ovum may still appear normal, or
show early degenerative changes. I n the early second stage,
there are no normal granulosa cells left, the ovocyte is dense,
amorphous and irregular; in the late second stage, the ovocyte
deteriorates rapidly, the vitelline membrane breaks around
which there is a loose organization of fibroblasts and wandering blood cells ; the hyaloid membrane of the theca is well developed. I n the third stage, there is a progressive shrinkage
of the follicle, a further infolding of the hyaloid membrane,
and a complete absorption of the thin fibroblastic meshwork
filling the cavity until eventually nothing remains but the many
hyaloid bands which may or may not enclose an irregular
central cavity.
The first and second stages were included as atretic follicles
in this study, the third stage was regarded as corpora atretica.
Rhesus monkeys had comparable numbers of ovocytes in the
pre- and postmenstrual period (Green and Zuckerman, '50).
Only at the time of ovulation is the number of follicles with
antra higher, but this small number cannot influence the total.
Unknown factors determine the number of ovocytes in the
ovary. The ovocytes in one monkey were equally divided between both ovaries. The numbers of oocytes in the right and
the left ovary differed greatly in only one monkey.
Careful attention was paid to the atresia of the follicles of
the different stages of development, For the primordial ovocytes it is sometimes difficult to determine whether the cell is
atretic or normal. I n every case where any doubt existed, the
cell was counted as normal. Our estimates of atresia may
therefore be somewhat low.
Comparison of the separate groups shows that the number
of atretic follicles increased in relation to the size of the follicle. I n all series this increase was relatively constant for
each group (table 2 ) . Thus, during the process of growth and
220
GERTRUDE J. VERMANDE-VAN ECK
maturation of the follicle the rate of atresia increases constantly. The largest fluctuations between the number of normal and atretic ova existed in the follicles with antra. Because
the ovariectomies were performed at different stages of
menstrual cycle, we could expect fluctuations in this group.
During the secretory phase of the cycle, 66% of the follicles
with antra were normal; 34% were atretic. This would indicate that in the monkey not all follicles with antra degenerate
at the time of ovulation. The total atresia of all three series
was low and remarkably constant: the averages were 4.5 f
0.5%; 4.1 2 0.5%; and 4.8 2 0.5%. This means that at any
time in the ovary of the monkey, about 4.5% of the existing
ovocytes are in the process of acute degeneration.
Seven days after irradiation practically no ova larger than
group 2 were recognizable, and after 14 days only ova surrounded with one layer of epithelial cells were present, and all
of the larger follicles were young corpora atretica. These facts
give us some insight into the rapidity of the atresia. Once
atresia occurs in a follicle the process was completed within
two weeks; for the small growing follicles the process required
less than one week. Sturgis ('49) estimated the first stage of
atresia to take place within one or two days, the second stage
were seen from the second and third days until the 10th day;
the third stage after about three weeks. Our findings after
x-rays correspond with those of Sturgis, who dated his estimates on the age of the corpora lutea and the presence of
luteinized tissue in the atretic follicles.
Atresia occurs after damage of the ovocyte. Whether the
damage is caused physiologically (from hitherto unknown
factors) or artificially (by x-rays) makes no difference in the
rapidity of the process. The constant atresia of 6 5 % of the
total ovocytes would result in a steady decrease of their number if no formation of new ova from whatever source occurred.
I f the duration of the atresia is known, and the percentage of
atresia is known by counting, a regression line for the number
of ovocytes in relation to the time can be plotted, using the
formula t, = a(l-r)n, in which t,= the number of ovocytes
NEO-OVOGENESIS I N T H E ADULT MONKEY
221
after n periods of atresia; a = the original number of ovocytes, and r the percentage atresia.
The percentage of atresia was 6 5 % in all series ; this gives
a decline in the curve which is much stronger than the decrease of the number of ovocytes in reality. The ovaries
would be practically exhausted within two years, which is in
contradiction to the findings. We even found a balance between atresia and new formation by comparing the mature
and immature monkeys. Both had the same number, and the
same death rate of ovocytes ( 6 5 % per week). The average
life of the ovocyte can then be calculated to range between 21
and 26 weeks, which gives us an average life of the ovocyte of
the rhesus monkey of about half a year. We have already calculated that the ovary, without new formation, would be
deprived of ovocytes within two years, which gives us the
theoretical maximum life of the ovocyte.
Only a limited number of follicles with antra were degenerating at any time of the menstrual cycle (av. 33%). This
degeneration was complete after 10-14 days. Consequently
the average time required for the growth of the mature follicle
from the large follicle without antrum is about 4-6 weeks; the
whole process of development is apparently much longer than
hitherto assumed. The total length of the process in the monkey is unknown, but the last step requires 4-6 weeks. For the
human, it is often accepted that the time required from primordial to mature follicle is 2-4 weeks. Several textbooks of
Obstetrics and of Histology give this statement. I n the literature, references are often made t o the original publications of
Robert Schroeder ( '15) and of Robert Meyer ( '13). However,
in their original publication such statements were not noted.
Our figures imply that continuous formation of new ova
occurs throughout sexual life. The number forming probably
decreases with aging of the monkey and finally ceases. The
human ovary is said to be devoid of ovocytes a few years after
the menopause. For the monkey it would be possible to follow
the rate of new formation by counting ovaries at different
222
GERTRUDE J. VERMANDE-VAN ECK
known ages. It would be helpful to study ovaries from monkeys that have attained advanced ages.
SUMMARY
The problem of postnatal ovogenesis was approached by
analyzing the number of normal and atretic ova in the rhesus
monkey.
Eight immature monkey ovaries (Yale Colony), 6 immature,
and 7 mature monkey ovaries (Carnegie Colony) were counted.
The counting technique described by Green and Zuckerman
( '50) was used. The follicles were grouped in 7 stages ranging from primordial to mature follicles. The normal and
atretic ova were determined separately.
The number of ovocytes differed widely among animals of
similar ages. The right and left ovaries of one monkey usually
contained about equal numbers of ovocytes.
The averages of the total number of ovocytes for the three
groups ranged between 50,120 2 10,600 and 60,810 116,470
per ovary, with an average atresia of 4.1 2 0.5 to 4.8 I+ 0.5%.
The distribution in the different stages of follicle development was constant.
The percentage of atretic ova was also constant for each
group.
The duration of the atresia was determined by x-irradiation
of the ovary with doses (1200 r) adequate to destroy all growing follicles. Atresia after irradiation occurred in 7 days.
The average and maximum life of the ovocytes were calculated (about 6 months and two years respectively) as was the
average time required for the growth of the mature follicle
from the large primary follicle (4 to 6 weeks).
ACKNOWLEDGMENTS
I should like t o express my gratitude to Dr. William U.
Gardner, Chairman of the Department of Anatomy, Yale
University School of Medicine, for his guidance and stimulating comments ; to Dr. George Corner, Carnegie Institution of
NEO-OVOGENESIS I N T H E ADULT MONKEY
223
Washington, Department of Embryology, Baltimore, for the
opportunity given me to study his material ; and to Dr. Colin
White, Department of Public Health, Yale University, for his
help in the statistical evaluation of the data.
LITERATURE CITED
ABERCROMBIE,
M. 1946 Estimation of nuclear population from microtome scetions. Anat. Rec., 9 4 : 238-247.
ALLEN,E. 1923 Ovogenesis during sexual maturity. Am. J. Anat., 31 :439-481.
ALLEN,E., AND R. N. CREADICK1937 Ovogenesis during sexual maturity. The
first stage, mitosis in the germinal epithelium, as shown by the colchicine technique. Anat. Rec., 69: 191-195.
ALLEN,E., J. P. PRATT,
Q. N. NEWELLAND L. J. BLAND 1930 Human ova from
large follicles; including a search f o r maturation divisions and observations on atresia. Am. J. Anat., 46: 1-53.
ARAI, H. 1920 On the postnatal development of the ovary (albino r a t ) , with
especial reference to the number of ova. Am. J. Anat., 87: 405-462.
COWPERTHWAITE,
M. M. 1925 Observations on pre and post pubertal oogenesis
in the white rat : Mus norvegicus albinus. Am. J. Anat., 36 : 69-89.
EVANS,
H. M., AND 0.SWEZY 1931 Ovogenesis and the normal follicular cycle in
adult mammalian. Memoirs o f Univ. of Calif., 9: 119-188.
GREEN, S. H., AND S. ZUCKERMAN1950 The number of oocytes in the mature
rhesus monkey (Macaca mulatta). J. Endocrin., 7: 194-202.
HAGGSTROM,P. 1921 Zahlenmassige Analyse der Ovarien eines 22 jahrigen
gesunden Weibes. Upsala l k . Forh., $6: XV, 1-52.
1920 Ein Fall von Thyreoaplasia unter
HANMAR,
J. A., AND T. J. HELLMANN
Beriicksichtigung gewisser innersekrctorischer und lymphoiden Organe.
Z. angew. Anat., 5: 218-267.
JONES, R. McC. 1949 The use of vital staining in the study of the origin of
germ cells in the female rat, Mus norvegicus. J. Morphol., 84: 293-334.
LATTA,J. S., AND E. S. PEDERSON
1944 The origin of ova and follicle cells from
the germinal epithelium of the ovary of the albino r a t as demonstrated
by selective intravital staining with India ink. Anat. Rec., 90: 23-35.
MEYER,R. 1913 Ueber die Beziehung der Eizelle und des befruchteten Eies
zum Follikelapparat, sowie des corpus luteum zur Menstruation. Ein
Beitrag zur normalen und pathologischen Anatomie und Physiologie des
Ovariums. Arch. f. Gyn., ZOO: 1-19.
MANDL,A. M., AND S. ZUCKERMAN1949 The number of normal and atretic ova
in the mature rat. J. Endocrin., 6: 426-435.
1950 Number of normal and atretic oocytes in unilaterally spayed
rats. J. Endocrin., 7 : 112-119.
1950 The effect of destruction of the germinal epithelium on the
number of oocytes. J. Endocrin., 7 : 103-111.
- -___
1950 The relation of age to numbers of oocytes. J. Endocrin., 7:
190-1 93.
224
GERTRUDE J. VERMANDE-VAN ECK
MANDL,A. M., AND S. ZUCKERMAN1950 Changes in ovarian structure following
the injection of carbolic acid into the ovarian bursa. J. Endocrin., 7:
227-235.
SCHROEDER,
R. 1915 Anatomische Studien zur normalen und pathologisehen
Physiologie des Menstruationszyklus. Arch. f. Gyn., 104 : 27-102.
SCHMIDT,
I. G., AND F. G. HOFFMAN 1941 Proliferation and ovogenesis in the
germinal epithelium of the normal mature guinea pig, as shown by the
colchicine technique. Am. J. Anat., 68: 263-273.
SCHWARZ,
0. H., J. C. YOUNGAND J. C. CROUSE 1949 Ovogenesis in the adult
human ovary. Am. J. Obstet. Gynaec., 58: 54-64.
SIMKINS,C. 8. 1932 Development of the human ovary from birth t o sexual
maturity. Am. J. Anat., 51 : 465-505.
SIMPSON,M. E., AND G. VAN WACENEN 1953 Response of the ovary of the monkey (Macaca mulatta) t o the administration of pituitary follicle
stimulating hormone (F.S.H.). Anat. Rec., 115: 370.
STURGIS,S. H. 1949 Rate and significance of atresia of the ovarian follicle of
the rhesus monkey. Contr. to Embryol., 33: 67-80.
SWEZY,O., AND M. N. EVANS 1929 Ovogenesis in the mammalia. Proc. SOC.
Exp. Biol. and Med., 2'7: 11.
VAN WAGENEN,
G. 1954 Personal communication.
VON HANSEMANN,
S. 1912 Ueber den Kampf der Eier in den Ovarien. Arch. f.
Entw. Mech., 35: 223-235.
WALDEYER,
W. 1870 Eierstoek und Ei. Wilhelm Engelmann, Leipzig.
WINIWARTER,
H. VON, AND G. SAINMONT
1908 Ueber die ausschliesslich post
fetale Bildung der dcfinitiven Eier bei der Katze. Anat. Anz., 32:
61 3-616.
ZUCKERNAN,
S., AND A. M. MANDL 1949 The number of normal and atretic ova
in the mature rat. J. Endoerin., 6 : 426-435.
S., S . H. GREENAND A. M. MANDL 1951 The proportion of ovarian
ZUCKERMAN,
follicles in different stages of development in rats and monkeys. J.
Anat., 85: 325-329.
Документ
Категория
Без категории
Просмотров
3
Размер файла
817 Кб
Теги
adults, ovogenesis, atresia, monkey, neo, ovocytes, consequences
1/--страниц
Пожаловаться на содержимое документа