The Importance of Androgen Metabolism in the Regulation of Reproductive Behavior in the Avian Male

Abstract

INTRODUCTIONIn a wide variety of vertebrate species, the repertoire of social behaviors associated with reproduction in the male, including heightened intermale aggression, courting of the female, and copulation, is dependent on gonadal hormones (Leshner, 1978). Because the effects of castration can be countered by treatment with testosterone (T) and because T is the primary androgen secreted by the testes in all species examined, it was assumed for many years that endogenous T was the hormone controlling reproductive activities in the male. Recent research in a variety of mammalian and avian species has cast doubt on this assumption. It now appears likely that T serves primarily as a prehormone, being metabolized to other hormones to exert its effects. The general schema seems to be that the testes produce T, which is released into the bloodstream and circulated throughout the body. Hormone-dependent tissues, such as the sexual accessory tissues and specific .