SITE-SPECIFIC EFFECTS OF TESTOSTERONE PROPIONATE ON THE PROSTATE OF RAT PRETREATED WITH 3,2'-DIMETHYL-4-AMINOBIPHENYL - DOSE-DEPENDENT INDUCTION OF INVASIVE CARCINOMAS

It has been shown that testosterone propionate (TP) strongly promotes induction of invasive carcinomas in previously initiated accessory sex organs. In this study, in order to clarify the dose-dependence of thi s promotion, TP was given at 3 different levels (high, medium or low d oses) using different sizes (2, 1 and 0.5 cm long) of Silastic tube fo r 40 weeks after administration of 3,2'-dimethyl-4-aminobiphenyl to ma le F344 rats. The data showed development of invasive carcinomas in th e dorso-lateral and anterior prostate and in the seminal vesicle to be dose-dependent with the high dose of TP being most effective for tumo r induction. Average levels of serum testosterone were approximately 8 00, 600, 300 and 150 ng/dl in rats given the high to low doses and in control rats, respectively. Development of neoplastic lesions in the v entral prostate demonstrated an inverse dependence on the dose of TP. These findings, together with previous data, suggest that the tumor-pr omoting potential of TP on rat prostate is unlikely to be simply due t o its androgenic action and other factors should also be considered.