title: Presence and localization of endothelin receptor in the rat ovary and its regulation by pituitary gonadotropins.
abstract: In the present study we examined the regulation of receptors for endothelin 1 (ET-1) in rat granulosa cells. We examined the localization and regulation of ET receptors in immature rat ovary and the effects of ET-1 on steroidogenesis in cultured rat granulosa cells. The ovaries used in autoradiography were derived from pregnant mare serum gonadotropin and human chorionic gonadotropin-treated immature rats. Granulosa cells were obtained from diethylstilbestrol-treated immature rats and incubated with 125I-ET-1. Granulosa cells were cultured with ET-1 in the presence or absence of ovine follicle-stimulating hormone. The concentrations of sex steroid hormones in conditioned media were measured by radioimmunoassay. The binding site for ET-1 was localized in the granulosa cells, but not in thecal and luteal cells. Follicle-stimulating hormone (FSH) induced a dose-dependent increase in specific binding for ET-1 to cultured rat granulosa cells. In contrast, luteinizing hormone (LH) induced a dose-dependent decrease in specific binding for ET-1 to cultured rat granulosa cells. Conversely, treatment with prolactin and several sex steroid hormones had no effects on the specific binding of ET-1. Treatment with ET-1 inhibited FSH-stimulated accumulation of progesterone and estradiol in cultured rat granulosa cells. The results indicate that both FSH and LH influence the expression of ET-1 receptor, and that ET-1 may play a regulatory role in the ontogeny of the granulosa cell.
authors.affiliation: Department of Obstetrics and Gynecology, Wakayama Medical College, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Otani
authors.forename: M
authors.initials: M
authors.lastname: Yamoto
authors.forename: H
authors.initials: H
authors.lastname: Fujinaga
authors.forename: R
authors.initials: R
authors.lastname: Nakano
mesh_terms: D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006065:Gonadotropins, Pituitary / Q000502:physiology*; D010053:Ovary / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017466:Receptors, Endothelin / Q000378:metabolism*; D012756:Sheep; D014018:Tissue Distribution
chemical_list: D019332:Endothelin-1; D006065:Gonadotropins, Pituitary; D017466:Receptors, Endothelin; D011374:Progesterone; D004958:Estradiol; D005640:Follicle Stimulating Hormone