Effects of growth hormone on FSH, insulin and triiodothyronine-mediated estradiol production by granulosa cells from prepubertal gilts in vitro

Abstract

Three experiments were performed using porcine granulosa cells from medium-sized follicles (2–4 mm) cultured in serum-free medium at a density of 2 × 106 viable cells per well. Cells were cultured in the presence of combinations of FSH, insulin, growth hormone (GH) and triiodothyronine (T3), and subsequent estradiol (E2) production was monitored. In the presence of insulin, a dose-dependent E2 production response to FSH was observed (exp. 1). However, in all experiments, E2 production was reduced (P < 0.05) by the inclusion of GH in the media. The inclusion 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. Key words: Granulosa cells, growth hormone, estradiol