The maturation of rabbit epididymal spermatozoa in organ culture: inhibition by antiandrogens and inhibitors of ribonucleic acid and protein synthesis.

Infertile spermatozoa from the proximal corpus epididymidis will become fertile when this epididymal segment is cultured 24 h in vitro with 5alpha-dihydrotestosterone (5alpha-DHT). The effect of antiandrogens and inhibitors of RNA and protein synthesis upon this 5alpha-DHT-induced sperm maturation was investigated. The response to 5alpha-DHT was abolished by cyproterone acetate, SKF 7690, actinomycin D, cycloheximide, puromycin, and the aminonucleoside analog of puromycin. Addition of cyproterone acetate or actinomycin D to a suspension of distal corpus spermatozoa did not change their fertilizing ability. Culture of segments of the distal corpus for 24 h with the same antiandrogens and RNA and protein synthesis inhibitors did not change the fertilizing ability of spermatozoa. These results indicate that the development of the sperm-fertilizing ability observed in the proximal corpus epididymidis in vitro in response to 5alpha-DHT is dependent upon binding of 5alpha-DHT and synthesis of new RNA and protein molecules by the target cell. They also indicate that antiandrogen and inhibitors of RNA and protein synthesis do not have a nonspecific toxic effect on spermatozoa during the time period studied. It is likely that the target cells are the epididymal epithelial cells rather than the spermatozoa themselves.