Follicle-stimulating hormone and somatomedin-C stimulate inhibin production by rat granulosa cells in vitro.
The direct effect of somatomedin-C (Sm-C) and FSH on inhibin production by rat granulosa cells in vitro has been examined. FSH stimulated accumulation of inhibin in culture media in a dose-dependent manner with maximal stimulation (6-fold) being observed at a dose of 300 ng FSH/ml. Addition of Sm-C (30 ng/ml) either alone or in the presence of FSH (3-300 ng/ml) increased inhibin production (up to 5-fold). Sm-C alone was effective over the physiological dose range of 3-100 ng/ml. Concomitant addition of FSH (100 ng/ml) and Sm-C (3-100 ng/ml) resulted in a significant increase in inhibin production at all doses of Sm-C. The dose-dependent effects of FSH and Sm-C were also time dependent with a synergistic effect apparent after 48 h of culture. The Sm-C induced FSH inhibitory activity of granulosa cell culture media was confirmed as authentic inhibin by the demonstration of a dose-dependent neutralization of this activity by a monoclonal antibody raised against purified bovine inhibin. The data indicate a direct role for both FSH and Sm-C in ovarian inhibin production and provide additional evidence for an autocrine-paracrine role for Sm-C in granulosa cell differentiation.
D000818:Animals; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D004357:Drug Synergism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007163:Immunosorbent Techniques; D007265:Inhibins / Q000096:biosynthesis*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D013002:Somatomedins; D007265:Inhibins; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone