Spermatogenesis: its regulation by testosterone and FSH.

It has been clear for decades that testosterone is a necessary prerequisite for the maintenance of established spermatogenesis in the adult testes, and for the restoration of spermatogenesis in testes induced experimentally to become azoospermic. In contrast, the possible involvement of FSH in regulating spermatogenesis in the adult mammal, though also studied extensively, continues to be debated in the literature. The mechanisms by which testosterone and FSH regulate spermatogenesis remain uncertain as well. This review focuses on our current understanding of the involvement of testosterone and of FSH in the maintenance and restoration of spermatogenesis in the adult testes, and discusses the emerging concept that testosterone and FSH serve as cell survival factors. Copyright 1998 Academic Press.