Ovarian Weight Gain Research Articles

Inhibition of the ovarian augmentation reaction by a chemical antiestrogen.

Inhibition by antiestradiol serum of ovarian weight gain and follicular growth in hypophysectomized immature rats given FSH and hCG suggested that gonadotrophin induced endogenous estrogen secretion plays a role in the ovarian augmentation reaction. We have studied the effects of a chemical estrogen antagonist, cis-clomiphene, on ovarian weight response to gonadotrophins in hypophysectomized immature female rats. We found that this antiestrogen inhibits the ovarian response to FSH and hCG. To our knowledge, this is the first demonstration of a direct effect of a chemical antiestrogen on the ovary, a result consistent with a role for intraovarian estrogen in follicular growth.

Ovulating-inducing activity of FSH in the rat.

Ovine LH or FSH administered 44 hr after a priming dose of PMS induced ovulation inhypophysectomized immature rats. A well-characterized and highly specific LH antiserum (A/S) showing no cross reactivity with NIH FSH, TSH, GH or pr.olactin or with serum and tissue proteinextracts, was used to test the ability of NIH-FSH or LH-free FSH to cause ovulation. Theminimal effective dose (MEID) of LH A/S blocking ovulation induced by 10 ug LH was 3.0 ul per rat whereas that for blocking ovulation induced by FSH (100 ug) was 1.0 ul. While the MEID of the LH A/S for inhibition of ovarian weight gain was about 3 times greater than forinhibition of ovulation induced by LH, that for suppression of ovarian weight gain and inhibition of ovulation induced by FSH were the same. Incubation of FSH with variable amounts of LH A/Sfollowed by removal of the LH A/S with anti-rabbit gamma globulin resulted in preparations having no LH contamination as indicated by the double immunodiffusion test. The ovulation inducing capacity ...

INHIBITOTY EFFECTS OF MELATONIN ON HCG-INDUCED STIMULATION OF UTERINE AND OVARIAN GROWTH IN INFANTILE MICE

Numerous experiments give evidence for an inhibitory effect of the pineal principle melatonin on sexual maturation in rodents. Melatonin certainly has a central mode of action, but may act at a peripheral level as well (Soffer et al., 1965; Yamashita et al., 1965; Hipkin, 1970; Debeljuk et al., 1971). We tested the ability of melatonin to affect the PMS and HCG-induced uterine and ovarian weight-gain in infantile mice. The animals used (NMRI/Han.) were 21 days old and weighed 8-11 g. They were kept under standardized conditions (LD 12:12, temperature 23 ± 0.5° C, humidity 40-60°%). In addition to an untreated group and a group receiving saline 4 groups were formed: I) Mice receiving HCG (Predalon) in saline s.c. on 3 consecutive days with total doses of 0.2, 0.4 and 0.8 I.U. per animal. The animals were injected contralaterally with 0.2 ml saline daily. II) Mice treated with HCG in the same manner as group I but receiving instead of saline 0.2 ml melatonin solution per day, with a total dose of 30 μg per animal. Ill) Mice which were treated on 3 consecutive days with PMS (Predalon-S) in saline, with total doses of 0.1, 0.25, 1.0 and 2.5 I.U. per animal. The animals were injected contralaterally with 0.2 ml saline per day. IV) Mice receiving the same PMS treatment as group III being injected with 0.2 ml melatonin solution instead of saline. The total doses of melatonin per animal were 30 μg and 150 μg.

The effects of some progestational steroids on pubertal ovulation in the rat

Fifteen progestational steroids, including many of the compounds which are currently employed clinically as components of oral contraceptive preparations, were tested for ability to suppress pubertal ovulation in the rat. All of the compounds tested, except ethynodiol diacetate, inhibited initial ovulation. The steroids tested could be divided into two groups based upon their effects on uterine weight. The pregnanes and dimethisterone decreased uterine weight, while the nortestosterone derivatives increased the weight of the uterus. Compound effects on ovarian weight and body weight gain are also reported.

Studies on a neuraminidase containing gonadotropin inhibitor substance in bovine pituitary extracts.

Fractions derived from whole bovine pituitary glands or bovine anterior lobes were found to inhibit the ovarian weight-gain activity of mixtures of ovine follicle stimulating hormone (FSH) and human chorionic gonadotropin (HCG), bovine FSH and HCG, or HCG alone. These fractions also inhibited the ovarian ascorbic acid depleting (OAAD) activity of HCG but not bovine luteinizing hormone (LH). Such effects were seen only when the gonadotropin inhibiting (GI) fraction was mixed with the gonadotropin prior to bioassay. Separate site injections of GI and gonadotropin abolished the inhibitory response. GI failed to inhibit endogenous secretions of gonadotropins in normal cycling female rats, as reflected by ovarian and uterine weights, ovarian histology and vaginal smear patterns. FSH and HCG, but not bovine LH, have been reported to require sialic acid for biologic activity. GI was shown to exhibit neuraminidase activity over a wide pH range. Because of this, it is suggested that a neuraminidase-like enzyme may...

Interrelationships of prostaglandin F2a and gonadotropins in the immature female rat.

Prostaglandin F2a was tested in immature female rats to measure its effect on gonadotropin activity. Neither ovarian weight gain nor ovulation were stimulated by PGF2a administration. Prostaglandin F2a did have an inhibiting effect on the results of PMS and HCG treatment, decreasing ovarian weight gain, and ovulation. PMS stimulation of uterine growth was enhanced by PGF2a. This enhancement is probably due to increased secretion of estrogen by the ovary or by altering the ratio of estrogens to progestogens in the circulation.

Gonadotrophin inhibiting and anti-fecundity effects of chloramiphene.

Chloramiphene (1-[p-β-di-ethylaminoethoxy) phenyl] −1, 2-diphenyl-2-chloroethylene) is a pituitary gonadotrophin inhibitor. In immature litter-mate female parabiotic rats (1 castrate: 1 intact), 0.1 mg/ kg/day inhibited ovarian weight gain by 50%. Larger doses yielded greater inhibition.

The influence of estrogen and androgen on the ovarian response of hypophysectomized immature rats to gonadotropins.

The effects of human chorionic gonadotropin (HCG), pregnant mares’serum gonadotropin (PMS), and anterior pituitary gonadotropin (APG) were studied singly and in combination with each other and with diethylstilbestrol (DES) and testosterone propionate (TP) on the ovaries of the hypophysectomized immature rat. Ovarian weight and histological changes produced by these treatments were noted. DES was found to augment APG, but not HCG or PMS. This augmentation was evidenced by ovarian weight gain and corpus luteum formation. Certain similarities of te effects of PMS, HCG, and APG to those of estrogen and androgen were found. TP antagonized the follicular development produced by APG and DES. HCG caused striking thecal luteinization of the cystic follicles produced by both PMS and APG, and a substantial ovarian weight gain. DES exerted protective effects on the ova and granulosa cells in various situations. “Combination follicles,” which were partially luteinized, yet containe dhealthy granulosa cells and ova, we...