Patterns of FSH and LH Secretion in the Developing Ram: the Influence of Castration and Replacement Therapy with Testosterone Propionate

Abstract

Pituitary gonadotropin secretion was studied in the prepubertal ram. Increases of both plasma FSH and LH, determined by radioimmunoassay, were observed in castrate rams ranging from 30 to 150 days of age. “Castrate” gonadotropin titers were markedly suppressed following daily testosterone propionate treatment; a gonadotropin rebound occurred after the withdrawal of the testosterone propionate therapy. The data suggest that the immature ram pituitary is capable of gonadotropin secretion and that androgen feedback effectively suppresses the plasma level of both FSH and LH.