there was a question on testicular atrophy posted earlier by someone. here's the abstract of a study i dug up:
Can J Comp Med 1985 Jul;49(3):333-6
The effects of androgens and gonadotropins on testicular development in the prepubertal rat.
Kennedy RI, Rawlings NC, Murphy BD.
Treatment of male rat pups from five to 34 days of age with dihydrotestosterone or 5 alpha-androstane-3 alpha, 17 beta-diol, resulted in reduced testicular size at 35 days of age. This appeared to be due to decreased tubular diameters and reduced spermatocyte numbers, especially late pachytene cells in stages X to XIII. In rat pups treated with dihydrotestosterone or 5 alpha-androstane-3 alpha, 17 beta-diol, treatment with luteinizing hormone resulted in some restoration of tubular diameter and spermatocyte numbers. In 5 alpha-androstane-3 alpha, 17 beta-diol treated rat pups partial restoration of testes size resulted from follicle-stimulating hormone treatment, but tubular diameter and spermatocyte numbers were depressed. Single serum samples collected at 35 days of age were analysed for luteinizing and follicle-stimulating hormone concentrations. These data indicated that the effects of administered androgens were due primarily to depression of circulating gonadotropin concentrations but a direct inhibition at the level of the testis could not be ruled out.