Follicle-stimulating hormone-mediated induction of functional luteinizing hormone/human chorionic gonadotropin receptors during monolayer culture of porcine granulosa cells.
The LH/hCG receptor content of porcine ovarian granulosa cells from 1- to 3-mm follicles can be increases to 4--5 times the preculture level during monolayer culture in serum-containing media supplemented with insulin and FSH. The binding of [125I]iodo-hCG declines during the first 2 days of culture, but then uniformly increases through 6 days, achieving a 14- to 15-fold increase relative to the 2-day level under optimal conditions. Analysis of receptor binding by autoradiography indicates that after 2 days, the number of cells specifically binding [125I]iodo-hCG increases significantly during culture, as does the intensity of binding on receptor-bearing cells. Granulosa cells in monolayer culture exhibit heterogeneous receptor induction, indicating that normalized [125I]iodo-hCG binding data cannot be used to estimate receptor concentration per cell. Receptor affinities in the initial and induced populations are identical. LH/hCG receptors induced in granulosa cells during culture are functional, as demonstrated by specific hCG-stimulated progesterone secretion. 17 beta-Estradiol produces a differential effect in vitro, generally increasing [125I]iodo-hCG binding with respect to FSH-induced levels but consistently depressing the subsequent hCG-stimulated steroidogenic response of cells bearing the induced receptor. The porcine granulosa cell monolayer system thus appears to be a useful model with which to study, in vitro, mechanisms of steroid and gonadotropin regulation of granulosa cell differentiation and overall follicular development.
D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D013552:Swine
D006063:Chorionic Gonadotropin; D007328:Insulin; D011956:Receptors, Cell Surface; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone