Mechanism of Action of Inhibin

Abstract
Cultured anterior pituitary cells have been used to study the mechanism of action of ovine testicular inhibin proteins. Exposure of cells to inhibin for 48 or 72 h produced dose-dependent inhibition of FSH but not LH content, whereas shorter incubation times with inhibin did not reduce FSH. These changes were the result of inhibition of FSH production by the cell cultures. Despite the time delay before content was suppressed, FSH- and LH-stimulated release (10 nM LHRH) and FSH spontaneous release (no LHRH) were significantly reduced within 6 h of incubation with inhibin. This effect on release was not observed with a more active semipurified inhibin fraction derived from rete testis fluid.