HYSTERECTOMY OF THE NEWBORN GUINEA-PIG, SUBSEQUENT EFFECTS ON THE OESTROUS CYCLE AND LIFE SPAN OF THE CORPORA LUTEA

SUMMARY Longer oestrous cycles result from neonatal hysterectomy than from hysterectomy in adult life. Section and cauterization of the utero-vaginal union also prolonged the vaginal closure period up to an average of 55 days. The destruction of the mesometrium did not lengthen the oestrous cycle. Uterine autografts in hysterectomized newborn guinea-pigs did not prevent the long cycles.

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THE EFFECT OF AUTOTRANSPLANTATION OF THE OVARIES TO THE KIDNEYS OR UTERUS ON THE OESTROUS CYCLE OF THE GUINEA-PIG

Journal of Endocrinology ◽

10.1677/joe.0.0410095 ◽

1968 ◽

Vol 41 (1) ◽

pp. 95-103 ◽

Cited By ~ 11

Author(s):

K. P. BLAND ◽

B. T. DONOVAN

Keyword(s):

Guinea Pig ◽

Functional State ◽

Guinea Pigs ◽

Follicular Development ◽

Oestrous Cycle ◽

Corpora Lutea ◽

Primordial Follicles ◽

Local Nature

SUMMARY Autotransplantation of the ovaries of guinea-pigs to either the uterus or the kidneys caused the degeneration of all luteal and follicular tissue with the exception of the primordial follicles situated in the periphery of the graft. Follicular development then took place and oestrus and ovulation occurred 10–11 days after transplantation. The corpora lutea formed at this ovulation were maintained in a functional state for more than 35 days when the ovaries were transferred to the kidneys but when ovarian grafts were made to the uterus a series of shortened vaginal cycles was observed. These results substantiate the local nature of the luteolytic abilities of the uterus in this species and imply the existence of a uterine luteolytic substance.

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

Journal of Endocrinology ◽

10.1677/joe.0.0500625 ◽

1971 ◽

Vol 50 (4) ◽

pp. 625-635 ◽

Cited By ~ 4

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.

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OESTROGEN AND PROGESTERONE AND THE FUNCTION OF THE CORPORA LUTEA IN THE GUINEA-PIG

Journal of Endocrinology ◽

10.1677/joe.0.0470225 ◽

1970 ◽

Vol 47 (2) ◽

pp. 225-230 ◽

Cited By ~ 21

Author(s):

K. P. BLAND ◽

B. T. DONOVAN

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Single Injection ◽

Glass Beads ◽

Oestrous Cycle ◽

Corpora Lutea ◽

Luteal Regression ◽

Oestradiol Benzoate

SUMMARY Regression of the corpora lutea in the guinea-pig could be accelerated by treatment with 10 μg. oestradiol benzoate daily over days 3–11 of the oestrous cycle. A single injection of 10 μg. oestradiol benzoate on day 3 was also effective. The luteolytic effect of oestrogen was abolished by hysterectomy, indicating that the uterus is involved in the mediation of the response. Progesterone (5 mg. daily over days 3–11) enhanced the luteal regression brought about by the presence of two glass beads in one horn of the uterus, but did not affect luteal size in otherwise intact females. Treatment of guinea-pigs with 5 mg. progesterone daily over days 2–5 or 4–7 failed to alter the length of the oestrous cycle.

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

Journal of Endocrinology ◽

10.1677/joe.0.0190081 ◽

1959 ◽

Vol 19 (1) ◽

pp. 81-86 ◽

Cited By ~ 27

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.

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PRODUCTION OF PROSTAGLANDINS BY THE EARLY PREGNANT GUINEA-PIG UTERUS IN VITRO

Journal of Endocrinology ◽

10.1677/joe.0.0610265 ◽

1974 ◽

Vol 61 (2) ◽

pp. 265-271 ◽

Cited By ~ 13

Author(s):

FELICITY M. MAULE WALKER ◽

N. L. POYSER

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Oestrous Cycle ◽

Corpora Lutea ◽

Significant Difference

SUMMARY The amounts of prostaglandins F2α (PGF2α) and E2 (PGE2) produced by homogenized, incubated, pregnant and non-pregnant guinea-pig uteri were compared. The sizes of the corpora lutea from these animals were considered in relation to the amounts of prostaglandins produced by their uteri. The amount of PGF2α produced by the uteri from day-15 bilaterally pregnant guinea-pigs was significantly less than that produced by uteri from guinea-pigs on day 15 of the oestrous cycle. Corpora lutea from the pregnant animals were maintained but those from the day 15 non-pregnant animals had regressed. There was no significant difference between the results obtained for PGE2. Results from day 15 unilaterally pregnant animals and day 25 bilaterally pregnant animals are also presented and their implications discussed. The findings reported here may well explain how, in the guinea-pig, the conceptus is able to neutralize the luteolytic effects of the uterus.

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PRODUCTION OF PROSTAGLANDINS BY THE GUINEA-PIG UTERUS

Journal of Endocrinology ◽

10.1677/joe.0.0540147 ◽

1972 ◽

Vol 54 (1) ◽

pp. 147-159 ◽

Cited By ~ 55

Author(s):

N. L. POYSER

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Oestrous Cycle ◽

Prostaglandin E ◽

Prostaglandin F

SUMMARY The production of prostaglandins by the uterus and the resting levels of prostaglandins in the uterus on selected days of the oestrous cycle were determined in guinea-pigs. Prostaglandin F2α was detectable in the guinea-pig uterus in small amounts on days 13, 14 and 15 of the cycle. Prostaglandin E2 was present in even smaller amounts on days 14 and 15. The homogenized guinea-pig uterus had the ability to biosynthesize prostaglandins, from endogenous precursors, during incubation on every day of the cycle studied. Four to six times more prostaglandin F2α than E2 was produced on any one day with the amounts of prostaglandins formed increasing towards the end of the oestrous cycle. Indomethacin inhibited the biosynthesis of prostaglandins by the guinea-pig uterus. The implications of these findings are discussed.

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

Journal of Endocrinology ◽

10.1677/joe.0.0530295 ◽

1972 ◽

Vol 53 (2) ◽

pp. 295-301 ◽

Cited By ~ 1

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.

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EFFECT OF INTRA-UTERINE FOREIGN BODIES AND OF PROSTAGLANDIN ADMINISTRATION ON PROGESTERONE SECRETION DURING THE OESTROUS CYCLE OF THE GUINEA-PIG

Journal of Endocrinology ◽

10.1677/joe.0.0700039 ◽

1976 ◽

Vol 70 (1) ◽

pp. 39-45 ◽

Cited By ~ 3

Author(s):

F. R. BLATCHLEY ◽

B. T. DONOVAN

Keyword(s):

Guinea Pig ◽

Corpus Luteum ◽

Foreign Bodies ◽

Glass Beads ◽

Oestrous Cycle ◽

Corpora Lutea ◽

Blood Samples ◽

Progesterone Secretion ◽

Prostaglandin F

SUMMARY The response of the guinea-pig corpus luteum to the luteolytic influence of glass beads placed in the uterus, or to prostaglandin administration, was followed by assay of the progesterone content of blood samples collected daily. Following the introduction of glass beads into the uterus early in the cycle, the secretion of progesterone was curtailed. Treatment with prostaglandin F2α over days 4–6 or 6–8 of the cycle temporarily depressed progesterone release without shortening the life of the corpora lutea. When the drug was administered over days 8–10, 10–12 or 12–14 the depression in progesterone was not followed by any recovery. These observations indicate that the response of the corpora lutea to a luteolytic influence changes during the oestrous cycle.

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CORPUS LUTEUM CONTROL IN HYSTERECTOMIZED GUINEA-PIGS

Journal of Endocrinology ◽

10.1677/joe.0.0320153 ◽

1965 ◽

Vol 32 (2) ◽

pp. 153-NP ◽

Cited By ~ 5

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.

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