Cytokine modulation of inhibin secretion in cultured rat granulosa cells

Abstract

Abstract In the present study, we examined the effects of tumour necrosis factor α (TNFα) and interleukin-1β (IL-1β) on inhibin secretion by cultured rat granulosa cells using immunoblotting and two-site enzyme immunoassay for inhibin A (α-βA dimer). FSH stimulated the secretion of the inhibin α-βA dimer (32 kDa) by the cells in a dose-dependent manner. In addition to the predominant 32 kDa inhibin α-βA dimer staining, staining of minor immunoreactive bands was also enhanced by FSH. TNFα alone did not have any effect on inhibin secretion. Immunoblot analyses using an antiserum against α-subunit and an antiserum against βA-subunit revealed a dose-dependent inhibition by TNFα of FSH-stimulated secretion of inhibin by rat granulosa cells. Similarly, TNFα inhibited in a dose-dependent manner FSH-stimulated inhibin secretion when measured using a two-site enzyme immunoassay. IL-1β alone did not exert any effect on inhibin secretion but it inhibited FSH-stimulated inhibin release in a dose-dependent manner (using both immunoblotting and a two-site assay for inhibin A). The present observations suggest that TNFα and IL-1β inhibit gonadotrophin-stimulated inhibin production by cultured rat granulosa cells. Journal of Endocrinology (1996) 151, 449–457