The Comparative Efficacy of Testosterone, Progesterone, and Dehydroepiandrosterone for the Maintenance of Fertilizing Capacity in Castrated Hamsters

The dosage of testosterone, dehydroepiandrosterone, and progesterone to maintain normal fertilizing capacity of epididymal spermatozoa for 12 days after castration was compared in hamsters. Fertilitytrialsconlirmed previous findings that hamster epididymal spenus are infertile 12 days after castration,in the present study, 12 daily consecutive injections of 100 �tg of testosterone maintained normal fertilizing capacity, but 1 mg daily of its precursor dehydroepiandrosterone was required to achieve the same response. However, sperms were infertile after 12 daily injections of progesterone (0.25 or 1 Ing). The ability of dehydroepiandrosterone to maintain fertilizing capacity in these experiments is attributed to peripheral cjnversion of dehydroepiandrosterone to testosterone at sites other than the epididymis. Pioneering studies of Benoit (1926) and Moore (1928) established that the maintenance of morphology and function in the epididymis depends on the testis, and that epididymal spermatozoa stay motile for a longer time when one or both testes are present. More recently, circulating testosterone has been shown to be important for sperm maturation in the epididymis of rabbits (Orgebin-Crist et at., 1971) and hamsters (Lubicz-Nawrocki, 1973a). The precise mode of action of testosterone, however, remains unclear. In some species, including the hamster, the epididymis has been claimed to synthesize dehydroepiandrosterone (3�3-hydroxyandrost-5-en17-one) and testosterone in vitro (Hamilton, 1971), and considerable hydroxysteroid dehydrogenase activity has been found in this organ (McGadey et at., 1966). The functional significance of androgen synthesis in the epididymis raises the question of whether production of testosterone by the epididymis observed in vitro also