Non-androgenic role of testis in enhancing ventral prostate growth in rats

This study was conducted to investigate whether the testis, aside from its ability to secrete androgen, is able to promote prostatic growth in rats. Increasing quantities of silastic capsules filled with crystalline dihydrotestosterone (DHT) were implanted subcutaneously into adult Sprague-Dawley rats at the time of bilateral epididymo-orchiectomy or sham operation on the testes. Control animals received empty capsules. Twenty-eight days later, the growth of the ventral prostate as measured by wet weight, DNA, and protein content per prostate was significantly greater in rats with intact testes than in orchiectomized rats. An overall increased growth was noted at all doses of exogenous DHT administered. Serum levels of luteinizing hormone in animals treated with DHT were undetectable. Serum levels of testosterone in intact rats treated with DHT were not significantly different from those in castrated rats. These observations suggest a non-androgenic role for the testis and, perhaps, epididymis in promoting prostatic growth in rats, and are consistent with the concept that a non-androgenic substance, produced from the testis and/or epididymis, is able to enhance prostate growth induced by androgen stimulation. The possibility that this phenomenon may play a role in the benign growth of the prostate observed in aging human males with decreased blood levels of androgen warrants consideration.