Interactions of Estrogen and Androgen with Gonadotropins on Ovarian Progesterone Production1

Abstract

In hypophysectomized immature female rats, treatment with estradiol-17β (E₂) in vivo for 3 days decreased the ovarian production of progesterone in response to luteinizing hormone (LH). Concomitant treatment with E₂ and purified follicle stimulating hormone (FSH) prevented this inhibitory action of E₂. The possibility of a positive interaction between E₂ and FSH was further substantiated by similar observations in vitro. While E₂ inhibited progesterone accumulation by cultured ovarian cells, this inhibitory action was antagonized by the concomitant presence of FSH in the culture medium. By contrast, dihydrotestosterone (DHT) increased progesterone accumulation by the ovarian cells; concomitant treatment with DHT and FSH further enhanced this stimulatory effect. These results are consistent with the notion that steroid hormones exert local modulatory influences on ovarian responses to gonadotropic hormone stimulation.