EFFECTS OF TESTOSTERONE, DIHYDROTESTOSTERONE AND ESTROGEN ON 3,2'-DIMETHYL-4-AMINOBIPHENYL-INDUCED RAT PROSTATE CARCINOGENESIS

Post-initiation effects of testosterone propionate (TP), alpha-dihydro testosterone (DHT) and ethinyl estradiol (EE) on 3,2'-dimethyl-4-amino biphenyl (DMAB)-prostate carcinogenesis in F344 rats have been investi gated by administration of each hormone individually or either androge n in combination with EE. DMAB plus TP resulted in induction of invasi ve adenocarcinomas in the lateral and anterior prostate and seminal ve sicles, as shown in a previous study, whereas DHT did not exhibit any positive modulation potential. Administration of EE together with TP p roduced increased carcinoma incidence in the lateral and anterior pros tate, from 17 and 28% to 70% and 80%, respectively. Dorsal prostate tu mors, all of the non-invasive in situ type, were also evident in 30% o f animals receiving both TP and EE. Rats treated with DHT plus EE, how ever, did not develop tumors. Our experiment thus provides evidence th at estrogen may play an important role in prostate carcinogenesis. (C) 1994 Wiley-Liss, Inc.