Inhibitory role of sex steroid in the regulation of ovarian follicle‐stimulating hormone receptors during pregnancy

Abstract

The present study was conducted to determine the role of sex steroids in the regulation of FSH receptors in pregnant rats. In the normal physiological condition, FSH bindings per unit ovarian weight (density of binding) and per 2 ovaries (total binding) increased during days 14-21 gestation. Scatchard plot analyses of the binding suggested that the increase in FSH binding was due to an increase in the number of FSH-binding sites. The plasma FSH concentration in pregnant rats was stable during the receptor change. In contrast, the plasma estradiol-17 beta concentration continuously increased from gestation day 14 to 21, and the testosterone level showed a large peak on gestation day 18. Estradiol-17 beta (one silastic plate containing 13 mg crystal)-implanted pregnant rats during 14-21 days of gestation induced significant decreases in the total FSH binding and ovarian weight on gestation day 21. Estradiol administration increased the plasma estradiol level 2.3-fold but did not change the FSH level. Testosterone or 5 alpha-dihydrotestosterone, a nonaromatizable androgen, did not influence the binding level under the same dose treatment. In contrast, continuous treatment with aminoglutethimide (2 plates containing 20 mg crystal), an inhibitor of adrenocortical steroidogenesis, for 7 days significantly increased the total FSH binding without a significant change in the ovarian weight. The plasma titers of estradiol and testosterone in pregnant rats treated with aminoglutethimide were reduced by 37% and 51%, respectively. Aminoglutethimide did not influence plasma FSH levels. These results suggest that circulating estradiol acts as a negative factor in the regulation of ovarian FSH receptors, at least during the second half of pregnancy. Other factor(s) that is (are) independent of sex steroids and FSH may contribute to FSH receptor induction.

Female testosterone, dominance rank, and aggression in an Ethiopian population of hybrid baboons

“…Studies of many mammalian species show that T concentrations rise around the time of ovulation [Baird, 1984;Gudermuth et al, 1998;Nubbemeyer, 1999], which suggests that T may be associated with normal sexual function and female sexual motivation [Fernandez-Guasti et al, 1991;Herbert, 1970;Sherwin, 1988]. During pregnancy, production of T increases substantially [Gudermuth et al, 1998;Humphreys et al, 1985;Tsutsui, 1992], and returns to baseline levels following parturition [Altmann et al, 2004].…”

Developmental Changes in Galanin Receptors in the Quail Oviduct and the Effect of Ovarian Sex Steroids on Galanin Receptor Induction1

“…A SILASTIC plate (1.5 ϫ 15 ϫ 2 mm; ϳ10 mg crystal/plate) made of a mixture of medical SILASTIC adhesive (silicone type, Dow Corning) and crystalline sex steroid (Sigma, St. Louis, MO) was intraabdominally implanted around the oviduct as described previously (17). To determine the normal change in uterine galanin receptors during oviduct development, female quails at 4, 6, 10, and 13 weeks of age were killed by decapitation in the second series of experiments.…”