Effect of an LH-RH antagonist on reproductive status of immature female rats.

Administration of the LH-RH antagonist, D-Phe2-D-Ala6-LH-RH (Wy-18, 185) to immature female rats from days 25--35 of age was without significant effect on day of vaginal opening (puberal onset), weights of the ovaries, uteri and anterior pituitary, and on ovarian histology on autopsy day 39.     

Ovarian LDH activity in gonadotropin-treated immature rats.

Lactate dehydrogenase (LDH) activity was studied in the ovaries of immature rats treated with pregnant mare serum gonadotropin (PMS). LDH activity increased sharply at 36 h after PMS injection in the ovarian tissue as well as in the blood. It was suggested that the increase of LDH activity in the ovary may be related to its increasing ability to secrete estrogen.     

Ovarian LDH activity in gonadotropin-treated immature rats

Summary Lactate dehydrogenase (LDH) activity was studied in the ovaries of immature rats treated with pregnant mare serum gonadotropin (PMS). LDH activity increased sharply at 36 h after PMS injection in the ovarian tissue as well as in the blood. It was suggested that the increase of LDH activity in the ovary may be related to its increasing ability to secret estrogen.     

Effect of an LH-RH antagonist on reproductive status of immature female rats

Summary Administration of the LH-RH antagonist, D-Phe²-D-Ala⁶-LH-RH (Wy-18, 185) to immature female rats from days 25–35 of age was without significant effect on day of vaginal opening (puberal onset), weights of the ovaries, uteri and anterior pituitary, and on ovarian histology on autopsy day 39.The technical expertise of J. Tracy is gratefully acknowleged.     

The involvement of serotonin in induced ovulation in the immature rat.

In pregnant mare's serum gonadotropin (PMS) treated immature rats the cortex, cerebellum, caudate nucleus and hypothalamus were isolated and analyzed for their serotonin (5-HT) content at 6-h intervals for 72 h. Results showed a general trend of significant variation occurring in days 1 and 3 after PMS injection with no major variations observed on the second day. The results obtained suggest a possible involvement of 5-HT in the control of ovulation.     

The involvement of serotonin in induced ovulation in the immature rat

Summary In pregnant mare's serum gonadotropin (PMS) treated immature rats the cortex, cerebellum, caudate nucleus and hypothalamus were isolated and analyzed for their serotonin (5-HT) content at 6-h intervals for 72 h. Results showed a general trend of significant variation occurring in days 1 and 3 after PMS injection with no major variations observed on the second day. The results obtained suggest a possible involvement of 5-HT in the control of ovulation.     

Reappearance of HCG-receptors in immature rat ovary after HCG-treatment is not due to receptor synthesis.

In 24-day-old rats the reappearance of ovarian HCG-receptors after the injection of 200 IU HCG in independent of protein synthesis. The reutilization of occupied receptors in immature female rats is due to dissociation of the receptor-hormone complex.     

Reappearance of HCG-receptors in immature rat ovary after HCG-treatment is not due to receptor synthesis

Summary In 24-day-old rats the reappearance of ovarian HCG-receptors after the injection of 200 IU HCG is independent of protein synthesis. The reutilization of occupied receptors in immature female rats is due to dissociation of the receptor-hormone complex.This work was supported in part by the Deutsche Forschungsgemeinschaft (SFB 46). Purified HCG was a gift of Schering AG, Berlin West. We thank Mrs Margarete Lindig and Mrs Rita Rudolph for assistance and Mr A. Schlegel for radioimmunological determinations.     

Effect of p-coumaric acid on immature estrogen treated and cyclic female mice

Oral administration of p-coumaric acid to estrogen-primed immature female mice exerts neither estrogenic nor anti-estrogenic activity, but when it is administered to cyclic female mice in single dose at proestrus or in repeated doses, induces alteration in estrus cycle, ovarian and uterine weight and structure.     

Effects of ovarian steroids on superoxide dismutase activity in the rat brain

The levels of manganese superoxide dismutase (MnSOD) and copper-zinc superoxide dismutase (CuZnSOD) were determined in appropriate subcellular fractions prepared from whole brain homogenates of cycling and long-term (3 week) ovariectomized (OVX) Wistar rats, and were compared to the levels found in corresponding samples prepared from OVX rats treated with progesterone (P) or estradiol 17B-benzoate (EB). The activity of both SODs was steady during the estrous cycle, except at proestrus, when MnSOD activity was elevated significantly. Bilateral ovariectomy resulted three weeks later in an increase of the MnSOD activity even higher than that recorded at proestrus. High post-castration MnSOD activity was lowered profoundly by exogenous P (2 mg) or EB (0.5 g), given s.c. to OVX animals 2 h or 24 h before sacrifice. Neither removal of the ovaries nor the hormone treatments affected the activity of CuZnSOD. These results suggest suppressive effects of ovarian steroids on MnSOD activity in the rat brain.     

Influences of dehydroepiandrosterone acetate on ovarian oocytes in mature cycling rats

Summary Degeneration of ovarian oocytes occurred to a remarkable extent in rats with polycystic ovaries induced by dehydroepiandrosterone acetate (DHA-Ac) administration. The ratio of degeneration oocytes, compared with the total oocytes examined, finally exceeded 70%.We thank Mrs M. Aikawa and Miss R. Araki for laboratory assistance, and Dr K. Araki and the Institute of Animal Experiments for other help.     

CNS stimulation effect on the sexual maturation of the female rat

Summary In the immature rat, CNS stimulants administration to pregnant mare serum gonadotropin (PMSG) primed rats resulted in significant (p<0.01) ovarian and uterine hypertrophy when compared to animals treated with PMSG only. Meanwhile precocious puberty was produced by pentylenetetrazol treatment alone. The results of this experiment may indicate that administration of CNS stimulants has a specific action on the release of endogenous gonadotropin.Supported by NIH grant no. RR 8111.National Institute of Health, MBS Graduate Trainee.     

Adrenalectomy,ovarian HCG-binding and the onset of female puberty in the rat

Summary The delay of puberty onset in female rats adrenalectomized before the 25th day of age is due neither to changes in the number of ovarian HCG-receptors nor to an altered hormone affinity of these receptors. It is assumed that glucocorticoids act on an intracellular level, in the ovarian cells, possibly by alterations of cyclic AMP-dependent phosphodiesterase activity.This work was supported in part by the Deutsche Forschungsgemeinschaft (SFB 46). Purified HCG was a gift of Schering AG, Berlin-West. We thank Mrs Margarete Lindig for assistance and Mrs Ursula Frigewski for secretarial help.     

Effect of p-coumaric acid on immature estrogen treated and cyclic female mice

Summary Oral administration of p-coumaric acid to estrogen-primed immature female mice exerts neither estrogenic nor anti-estrogenic activity, but when it is administered to cyclic female mice in single dose at proestrus or in repeated doses, induces alteration in estrus cycle, ovarian and uterine weight and structure.The authors wish to thank Dr S. C. Pakrashi and his associates of Medicinal Chemistry Department for isolating the compound. Thanks are also due for granting Senior Research Fellowship to P.P. and Junior Research Fellowship to S.N.K. respectively.     

Effect of continuous illumination on secretion of pregnane compounds by the rat ovary

Summary Differences in the secretion of pregnance compounds from rats with follicular polycystic ovaries under constant light and with normal preovulatory ovaries under light-dark conditions were compared. The injection of LH greatly increased the secretion of progesterone. 5-pregnane-3,20-dione and 3-hydroxy-5-pregnan-20-one, in both types of ovaries, but the response of the two progesterone metabolites in the polycystic ovaries was low, suggesting low 5-reductase activity.Acknowledgments. The authors thank the Endocrinology Study Section, NIADDK, Bethesda, MD, USA. for their gift of LH. This study was supported by Research Grant No. 466 154 from the Ministry of Education, Science, and Culture, Japan.     

Possible involvement of indolamines in the glycogenic effect of the convulsant methionine sulfoximine in rat brain.

The aim of the present investigation was to look for the mechanisms causing disturbances in carbohydrate metabolism during the action of the epileptogenic agent methionine sulfoximine. The levels of glucose, glycogen, and indolamines were measured in seven different regions of rat brain. Methionine sulfoximine induced a decrease in serotonin level which was roughly dose-dependent. There were no obvious changes in tryptophan and 5-hydroxyindoleacetic levels in any area. Methionine sulfoximine induced the known increase in glucose and glycogen levels. The direct precursor of serotonin. 5-hydroxytryptophan, and benserazide (a decarboxylase inhibitor) were then injected into rats in association with methionine sulfoximine. In this case, methionine sulfoximine failed to induce seizures. Moreover, the serotonin level was unchanged and the carbohydrate content did not significantly increase. There was only a rise in 5-hydroxyindoleacetic acid level. This work shows a striking parallelism between serotonin decrease and glycogen increase.     

Possible involvement of indolamines in the glycogenic effect of the convulsant methionine sulfoximine in rat brain

Summary The aim of the present investigation was to look for the mechanisms causing disturbances in carbohydrate metabolism during the action of the epileptogenic agent methionine sulfoximine The levels of glucose, glycogen, and indolamines were measured in seven different regions of rat brain. Methionine sulfoximine induced a decrease in serotonin level which was roughly dose-dependent. There were no obvious, changes in tryptophan and 5-hydroxyindoleacetic levels in any area. Methionine sulfoximine induced the known increase in glucose and glycogen levels. The direct precursor of serotonin, 5-hydroxytryptophan, and benserazide (a decarboxylase inhibitor) were then injected into rats in association with methionine sulfoximine. In this case, methionine sulfoximine failed to induce seizures. Moreover, the serotonin level was unchanged and the carbohydrate content did not significantly increase. There was only a rise in 5-hydroxyindoleacetic acid level. This work shows a striking parallelism between serotonin decrease and glycogen increase.     

Activité gonadotrope d'un extrait d'urines de femmes en ménopause

Summary In agreement with earlier observations on hypophysectomized male rats, a purified extract from pooled menopausal urine has been shown to contain follicle-stimulating (FSH) as well as luteinizing (LH) activity. Its administration to immature hypophysectomized female rats increased ovarian and uterine weights and induced follicle growth and the formation of corpora lutea. If the activity of the extract is measured in standardized units by bioassay in intact female mice using the uterine weight, the dose needed for corpus luteum formation in the hypophysectomized female rat seems to be approximately ten times higher than the dose producing interstitial cell repair and complete spermatogenesis in the hypophysectomized male.

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2^e Communication: Effets sur les ovaires de rates impubères hypophysectomisées.     

Appearance of sperm activation factors in the ovary of the sea urchinHemicentrotus pulcherrimus with maturation

Summary Ovaries of the sea urchinHemicentrotus pulcherrimus were extracted with 70% ethanol. The extracts were polarographically assayed for respiration-stimulating activity toward homologous spermatozoa. The data of the bioassay and light microscopic observation on thin sections of the ovaries showed detectable activity only in mature ovaries.We thank the Misaki Marine Biological Station for kindly supplying us with specimens. This work was supported in part by a grant from the Ministry of Education, Science and Culture of Japan.     

Effect of continuous illumination on secretion of pregnane compounds by the rat ovary

Differences in the secretion of pregnane compounds from rats with follicular polycystic ovaries under constant light and with normal preovulatory ovaries under light-dark conditions were compared. The injection of LH greatly increased the secretion of progesterone. 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one, in both types of ovaries, but the response of the two progesterone metabolites in the polycystic ovaries was low, suggesting low 5 alpha-reductase activity.