Secretion of inhibin by chicken granulosa cells in vitro.

Inhibin activity was investigated using chicken granulosa cell culture medium. Chicken granulosa cells were collected individually from the largest follicle (F1 follicle) and the third largest follicle (F3 follicle) of the ovary, dispersed using enzyme and incubated in a suspension method or cultured in a monolayer method in vitro. Culture medium was assessed for follicle-stimulating hormone (FSH) inhibiting (inhibin) activity using the rat anterior pituitary cell culture method. The FSH secretion from cultured rat pituitary cells was suppressed by experimental increasing of the amounts of granulosa cell culture medium in a dose-dependent manner, though luteinizing hormone (LH) secretion was not affected in a dose-dependent manner. Inhibin activity of the granulosa cell culture medium derived from F1 follicles was higher than that from F3 follicles. These results suggest that chicken granulosa cells secrete inhibin-like substance(s) and that the F1 follicle may secrete a larger amount of inhibin than the F3 follicle.