VI.—Studies on the Reproductive System in the Guinea-Pig : Observations on the Ovaries, with special reference to the Corpus Luteum

1935 ◽  
Vol 54 ◽  
pp. 56-66 ◽  
Author(s):  
Thomas Nicol
Keyword(s):  
Guinea Pig ◽  
Special Reference ◽  
Corpus Luteum ◽  
Reproductive System ◽  
Guinea Pigs ◽  
Post Partum ◽  
Corpora Lutea ◽  
Tabular Form

The object of the present paper is to put upon record for the guinea-pig data which I have collected regarding (1) the relation between the number of young in a litter and the number of corpora lutea of pregnancy in the ovaries, (2) the distribution of corpora lutea between the two ovaries in two successive ovulations, and (3) the utilisation of the uterine horns in successive pregnancies. The data were obtained in the course of other researches and are arranged in tabular form (Tables I and II). The records from which they have been collected refer to 40 female guinea-pigs killed post partum, of which 16 were pregnant and 24 had not been reimpregnated. The size of the previous litter is known for 38 of these females; both ovaries were serially sectioned at 10 microns in the 40 animals, but in 4 the records of only one ovary were preserved.

THE EFFECT OF HYPOPHYSIAL STALK-SECTION ON THE CORPUS LUTEUM OF THE GUINEA-PIG

1971 ◽  
Vol 50 (4) ◽  
pp. 625-635 ◽  
Author(s):  
DOREEN V. ILLINGWORTH ◽  
J. S. PERRY
Keyword(s):  
Growth Rate ◽  
Guinea Pig ◽  
Corpus Luteum ◽  
Guinea Pigs ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Normal Cycle ◽  
Luteal Regression ◽  
Normal Regression ◽  
And Function

SUMMARY The effects of hypophysial stalk-section on the growth and function of the corpus luteum of the non-pregnant guinea-pig have been compared with the effects of hypophysectomy (as previously described) and with the effects of prolactin administered to hypophysectomized animals. Stalk-section soon after ovulation did not impair the growth of the corpora lutea nor their ability to secrete progesterone. Stalk-section before day 9 of the oestrous cycle prevented the normal regression of the corpora lutea; they continued to grow and 3 weeks after ovulation were as large as those of pregnant animals, or of non-pregnant hysterectomized guinea-pigs. The corpora lutea regressed irregularly during the following 2 weeks. When performed on, or later than day 9, stalk-section did not prevent luteal regression at the normal time. Administration of prolactin (10 i.u./day) to hypophysectomized guinea-pigs restored the growth-rate of the corpora lutea, which reached sizes comparable to those of the normal cycle, and those of stalk-sectioned animals, by 10 days after ovulation. Our results indicate that prolactin can have substantial luteotrophic activity in the guinea-pig.

CORPUS LUTEUM CONTROL IN HYSTERECTOMIZED GUINEA-PIGS

1965 ◽  
Vol 32 (2) ◽  
pp. 153-NP ◽  
Author(s):  
R. DEANESLY ◽  
J. S. PERRY
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Guinea Pigs ◽  
Luteal Phase ◽  
Corpora Lutea ◽  
Vaginal Opening

SUMMARY Interruption of the prolonged luteal phase in hysterectomized guinea-pigs, followed by vaginal opening, can be caused by substances affecting the hypothalamus and hypophysis, which check gonadotrophin output. In the present experiments, both progesterone and reserpine were effective and caused regression of the corpora lutea. It may be concluded that in the guinea-pig, as in the sow and the sheep, the corpora lutea of hysterectomy do not function independently of the hypophysis. The uterine factor associated with normal cyclic corpora lutea regression, which is lacking after hysterectomy, presumably acts on the hypophysis rather than directly on the corpora lutea.

AN EXPERIMENTAL STUDY OF POST-PARTUM ENDOMETRIAL REPAIR IN THE GUINEA-PIG AND RAT

1952 ◽  
Vol 8 (2) ◽  
pp. 162-NP
Author(s):  
A. SHARMAN
Keyword(s):  
Experimental Study ◽  
Guinea Pig ◽  
Corpus Luteum ◽  
Guinea Pigs ◽  
Post Partum ◽  
The Third ◽  
Endometrial Regeneration

An experimental study was made of post-partum endometrial regeneration in twenty-one healthy guinea-pigs and in twenty healthy rats. To serve as controls, one guinea-pig was killed on the day of parturition and another 6½ days following parturition: three rats were killed on the day of parturition and one 6½ days following parturition. All the remaining animals were ovariectomized. Groups of three were killed at the following intervals after parturition, viz.: 22, 40, 58, 84 hr. and 6½ days. In each group, one animal was left uninjected, another injected with oestrogenic hormone and the third injected with corpus luteum hormone. Endometrial regeneration appeared to proceed normally in all the animals.

THE PROGESTERONE CONTENT OF THE GUINEA-PIG CORPUS LUTEUM DURING THE REPRODUCTIVE CYCLE AND AFTER HYSTERECTOMY

1959 ◽  
Vol 19 (1) ◽  
pp. 81-86 ◽  
Author(s):  
I. W. ROWLANDS ◽  
R. V. SHORT
Keyword(s):  
Guinea Pig ◽  
Life Span ◽  
Corpus Luteum ◽  
Guinea Pigs ◽  
Hormonal Control ◽  
Corpora Lutea ◽  
High Concentration ◽  
Threefold Increase ◽  
High Level ◽  
Very High

SUMMARY Progesterone in the corpora lutea of unmated, pregnant and hysterectomized guinea-pigs was assayed chromatographically using a modification of the procedure described by Short [1958b]. Its concentration on the 6th day after ovulation was similar in unmated and pregnant animals. By the 11th to 13th day the concentration in non-pregnant animals had decreased by one-half, but in the pregnant animals the amount was unchanged. A two- to threefold increase occurred between the 11th to 13th and the 21st to 23rd day which, it is suggested, coincides with the production of a luteotrophin. Throughout the remainder of pregnancy the concentration of progesterone in the corpus luteum was maintained at a high level. The results are compared with those that have been obtained in other species. A very high concentration of progesterone was found in the corpora lutea of hysterectomized guinea-pigs. The use of this experimental animal is suggested for further work on the hormonal control of the life-span of the corpus luteum.

GONADAL HORMONES AND THE CONTROL OF OVULATION IN THE GUINEA-PIG

1972 ◽  
Vol 55 (3) ◽  
pp. 599-607 ◽  
Author(s):  
B. T. DONOVAN ◽  
A. N. LOCKHART
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Acute Treatment ◽  
Gonadal Hormones ◽  
Time Of Day ◽  
Gonadal Steroids ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate

SUMMARY The release of ovulating hormone after acute treatment with gonadal steroids, or corpus luteum removal on different days of the oestrous cycle, was studied in the guinea-pig. Injection of 25, 50 or 100 μg oestradiol or 2·5 mg progesterone on day 13 of the cycle had no effect upon gonadotrophin secretion as judged by follicular histology, but markedly altered the sizes of the corpora lutea of the previous ovulation. Treatment with oestradiol on day 14 did not elicit gonadotrophin secretion. However, administration of the same hormones to animals given 10 μg oestradiol benzoate 24 h earlier caused ovulation or follicular luteinization. Progesterone (2·5 mg) appeared least effective in stimulating gonadotrophin release; 25 μg oestradiol were more effective when given at 12.00 h than at 24.00 h but treatment with both hormones caused ovulation when given at either time of day. Luteal volumes were not affected. Removal of corpora lutea during the second half of the cycle advanced the time of expected ovulation to day 15 or earlier when the procedure was carried out on days 8 or 9, but not on days 10–13. It is concluded that 4–5 days must elapse between the fall in plasma progesterone level associated with corpus luteum regression and the release of ovulating hormone.

THE RELATIONSHIP BETWEEN THE UTERUS AND OVARIES DURING EARLY PREGNANCY IN THE GUINEA-PIG

1972 ◽  
Vol 53 (2) ◽  
pp. 295-301 ◽  
Author(s):  
F. R. BLATCHLEY ◽  
B. T. DONOVAN
Keyword(s):  
Guinea Pig ◽  
Early Pregnancy ◽  
Guinea Pigs ◽  
Uterine Horn ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Luteal Regression ◽  
Experimental Animals ◽  
Decidual Reaction ◽  
The Relationship

SUMMARY In mated guinea-pigs one uterine horn was rendered sterile by ligation of the oviduct 2 or 3 days after finding spermatozoa in the vaginal smear. Two glass beads were inserted into the sterile horn on each of days 3–12 and on day 14 in experimental animals but not in controls. At autopsy on day 20 large corpora lutea were present in both ovaries of the control animals. The presence of beads that had been introduced on days 3 and 4 and on days 10–14 resulted in marked regression of the corpora lutea in the adjacent ovary, in the absence of a decidual reaction in the uterus, while luteal enlargement typical of pregnancy occurred in the contralateral ovary. Beads inserted on days 5–8 caused decidualization in the sterile horn but did not induce premature luteal regression in the ipsilateral ovary.

scholarly journals The functions of the corpus luteum. II.—The experimental production of placentomata in the mouse

1929 ◽  
Vol 104 (729) ◽  
pp. 183-188 ◽  
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Corpora Lutea ◽  
Experimental Production ◽  
Unmated Female ◽  
Decidual Tissue ◽  
Uterine Mucosa

During the luteal phase of the cycle in many mammals, notably in the rabbit, ferret, and dog, the uterus undergoes changes which are designed to facilitate the implantation of the fertilised ovum. In other animals, such as the guinea-pig(5), the uterine changes during the luteal phase are histologically less obvious, but physiologically the uterine mucosa is in a peculiar condition of irritability. Injury to the mucosa at this time results in the production of large blocks of decidua-like tissue, to which the terms placentomata or deciduomata have been given. It has been shown by Marshall, Hammond, Loeb and others that the presence of the corpus luteum is essential for these post-ovulative uterine changes, and therefore that the corpus luteum is directly or indirectly responsible for their production. In the rabbit decidual tissue can only be induced to develop when functional corpora lutea are present in the ovary. In the guniea-pig (Loeb, 5) placentomata can be produced during the post-ovulation phase of the cycle in the unmated female, but in the rat Long and Evans (6) were unable to obtain a similar result. This discrepancy is undoubtedly due to the fact that in the short diœstrous cycle of the rat the corpora lutea undergo comparatively little development, whereas in the guinea-pig the cycle is longer and the corpora luteá are known to become active. During the pseudo-pregnancy which follows sterile copulation in the rat (Long and Evans, 6) and also during lactation (Corner and Warren, 2) placentomata can be produced. During both of these times corpora lutea develop to a greater extent than during the diœstrous cycle and become functional.

CHANGES IN THE CONCENTRATIONS OF CORTISOL AND CORTICOSTERONE IN THE PLASMA AND ADRENAL GLANDS OF THE GUINEA-PIG FROM BIRTH TO WEANING

1974 ◽  
Vol 63 (3) ◽  
pp. 483-488 ◽  
Author(s):  
M. DALLE ◽  
P. DELOST
Keyword(s):  
Adrenal Gland ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Plasma Cortisol ◽  
Adrenal Glands ◽  
Post Partum ◽  
Cortisol Secretion ◽  
Male And Female ◽  
Steady Level ◽  
Very High

SUMMARY Concentrations of cortisol and corticosterone in the plasma and adrenal glands of male and female guinea-pigs were estimated throughout the first postnatal day and thereafter at intervals up to 3 weeks of age. In the guinea-pig, the basal level of cortisol secretion is established more slowly than in other species. The concentration of plasma cortisol is very high at birth, with a marked fall between days 1 and 10 post partum and then a steady level from day 10 to 20, the time of weaning. At day 10 the values for plasma cortisol and corticosterone approach the lower ones found in the adult. There were peaks in the amounts of corticosteroids found in the adrenal gland at 50 h, 4 and 7 days and these may have been due to increased hormonal synthesis between days 2 and 8.

scholarly journals The corpora lutea of the mouse, with special reference to fat accumulation during the œstrous cycle

1930 ◽  
Vol 106 (747) ◽  
pp. 578-595 ◽  
Keyword(s):  
Special Reference ◽  
Corpus Luteum ◽  
Experimental Work ◽  
Laboratory Animals ◽  
Corpora Lutea ◽  
Mouse Ovary ◽  
Short Account ◽  
Cellular Degeneration ◽  
Pregnancy And Lactation ◽  
Considerable Period

Although the histological literature on the corpus luteum is very extensive, a description of cellular and fat changes in the organ, which distinguishes between the corpora lutea of ovulabion, pseudo-pregnancy, pregnancy, and lactation where these are differentiated, is still lacking for some laboratory animals. In view of experimental work now in progress, it was thought that a short account of the mouse corpus luteum on these lines might be of value. In the absence of pregnancy, old corpora lutea persist for a considerable period in the mouse ovary, and after the initial signs of cellular degeneration, which are not always very obvious, further changes are slow to occur. With suitable histological methods, however, it is possible to distinguish, even after they are fully developed, the corpora lutea belonging to the last one and sometimes two or more oestrous periods.

IN-VITRO STEROIDOGENESIS OF NEWLY FORMED CORPORA LUTEA AND THE NON-LUTEAL OVARY IN THE RAT, RABBIT, HAMSTER AND GUINEA-PIG

1980 ◽  
Vol 84 (1) ◽  
pp. 101-108 ◽  
Author(s):  
P. F. TERRANOVA ◽  
S. K. SAIDAPUR ◽  
G. S. GREENWALD
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Ovarian Function ◽  
Serum Testosterone ◽  
The Other ◽  
Corpora Lutea ◽  
Serum Progesterone ◽  
Antral Follicles ◽  
Baseline Levels

The steroidogenic abilities of the newly formed corpus luteum (8–10 h after ovulation) and the non-luteal ovary were compared in the guinea-pig, hamster, rabbit and rat using an invitro incubation technique. Histologically, newly formed rat corpora lutea (CL) were highly luteinized whereas the CL of the rabbit and guinea-pig were only partially luteinized. The CL of the hamster showed the least amount of luteinization. Serum progesterone was highest in the rat (18 ± 3 (s.e.m.) ng/ml). In the hamster, it was about 8 ng/ml, whereas in the rabbit and guinea-pig it was about 1 ng/ml. Serum androstenedione ranged between 0·5 and 1 ng/ml. Serum testosterone was lowest in the hamster (60 pg/ml) and highest in the rabbit (470 pg/ml), whereas in the rat and guinea-pig, testosterone levels were similar (about 240 pg/ml). Serum oestrogens were at baseline levels in all species. The CL of the rat exhibited considerably greater steroidogenic ability than the CL of the other species, producing 70 ± 6 ng progesterone/mg per h, 215 ± 14 pg androstenedione/mg per h, 49 ± 3 pg testosterone/mg per h, 3 pg oestrone/mg per h and 1 pg oestradiol/mg per h. Rabbit CL produced only progesterone (7 ± 2 ng/mg per h). Newly formed hamster CL produced none of the above steroids. In general, the ability of the CL to produce progesterone in vitro correlated with the degree of luteinization found by histological observation. Guinea-pig CL were embedded deeply in the ovary and could not be obtained without damage. Consequently, a portion of the ovary containing a corpus luteum was incubated. There was no difference in the steroid production by this portion of the ovary compared with the non-luteal ovary. The non-luteal ovary of the rat produced the highest amount of progesterone (10 ± 2 ng/mg per h). The guinea-pig non-luteal ovary produced about 5 ± 2 ng progesterone/mg per h, whereas the non-luteal ovary of the rabbit did not produce any. On the other hand, the hamster non-luteal ovary lost progesterone. Non-luteal ovaries from all species produced androgens. The non-luteal ovary of the guinea-pig contained especially large numbers of atretic antral follicles. The guinea-pig non-luteal ovary produced extremely large amounts of androstenedione (1110 ± 210 pg/mg per h) and testosterone (606 ± 154 pg/mg per h) compared with the amounts produced by the non-luteal ovary of the rat, hamster and rabbit. In the non-luteal ovary, interstitium and atretic antral follicles are the probable source of androgens. Oestrogen production by the non-luteal ovary was at baseline levels in the four species studied correlating with the absence of healthy antral follicles. The results indicate the extreme species differences that exist in ovarian function in the early postovulatory period.

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