The effect of metabolites of testosterone on the development of fertilizing ability by spermatozoa in the epididymis of castrated hamsters.

The effects of testosterone, 17beta-hydroxy-5alpha-androstane-3-one (5alpha-dihydrotestosterone; 5alpha-DHT), 5alpha-androstane-3alpha, 17beta-diol (3alpha-androstanediol; 3alpha-diol) and 5alpha-androstane-3beta, 17beta-diol (3beta-androstanediol; 3beta-diol) on the development of fertilizing ability by spermatozoa in the epididymis were compared in castrated hamsters. The left corpus epididymidis was ligated for 14 days in intact and castrated animals to prevent the in-flow of spermatozoa into the cauda epididymidis and the ductuli efferentes were bilaterally ligated. The fertilization rate of spermatozoa in the left cauda epididymidis of control animals decreased to 71.1% after 14 days whereas that of spermatozoa in the unobstructed right cauda epididymis remained at the control level of 100%. After castration, 50 mug testosterone, 25 mug 5alpha-DHT and only 9 mug 3alpha-diol/day were the minimal doses that facilitated normal development of fertilizing ability but 75 mug testosterone, 37.5 mug 5alpha-DHT and 12.5 mug 3alpha-diol/day were required to maintain sperm survival at the control level. However, 3beta-diol was ineffective for both sperm maturation and survival.