EFFECTS OF GROWTH-HORMONE ON FSH, INSULIN AND TRIIODOTHYRONINE-MEDIATED ESTRADIOL PRODUCTION BY GRANULOSA-CELLS FROM PREPUBERTAL GILTS IN-VITRO

Three experiments were performed using porcine granulosa cells from me dium-sized follicles (2-4 mm) cultured in serum-free medium at a densi ty of 2 x 10(6) viable cells per well. Cells were cultured in the pres ence of combinations of FSH, insulin, growth hormone (GH) and triiodot hyronine (T3), and subsequent estradiol (E2) production was monitored. In the presence of insulin, a dose-dependent E2 production response t o FSH was observed (exp. 1). However, in all experiments, E2 productio n was reduced (P < 0.05) by the inclusion of GH in the media. The incl usion of T3 augmented the E2 response to insulin, an effect attenuated by GH. We conclude that GH, at the dose employed, is inhibitory to E2 production in granulosa cells of medium-sized ovarian follicles.