The Influence of the Testis on the Survival of Spermatozoa in the Epididymis of the Golden Hamster, Mesocricetus Auratus

Summary. If both testes are removed and both epididymides are allowed to remain in situ in the golden hamster, the period of sperm survival in the tail of the epididymis is reduced by about half, since the spermatozoa lose their capacity to fertilize in 10 to 12 days. This contrasts with the 20- to 24-day survival of epididymal spermatozoa when one or both testes are present. It appears that only one testis is needed to ensure the normal survival of spermatozoa in both epididymides. Replacement of testosterone by a subcutaneous implant in bilaterally gonadectomized males resulted in normal sperm survival. Assessment of the ratio of live to dead spermatozoa showed that the ultimate loss of fertilizing capacity by the spermatozoa in both intact and gonadectomized males was not at first due to an increased incidence of dead spermatozoa in the epididymis, though progressively more dead and degenerated spermatozoa were gradually to be seen in the samples. The fertilizing capacity of the spermatozoa was lost more rapidly (within 8 days) in gonadectomized animals if they were also hypophysectomized. Administration of HCG to these animals failed to maintain normal viability in the spermatozoa. A gradual decrease in the occurrence of 'light' cells in the lining tissue of the duct is reported, following gonadectomy. It is concluded that circulating androgen is unquestionably required for the normal survival of spermatozoa in the tail of the hamster epididymis and that it probably achieves its effect through its influence on the epididymal epithelium. The findings are discussed in relation to the general hormonal control of sperm survival in the epididymis.