The Nb rat prostatic adenocarcinoma model has served as an animal model for testing various chemotherapeutic agents. Herein this preliminary report, the tumor Nb PRST-1 Ca was evaluated in 25 animals with testosterone, dihydrotestosterone, orchiectomized and control treatments. Tumor growth curves were determined and show a significant difference on day 13 (T-test) between the control group and treatment groups. Metastases were found in the lungs of all animals and a remarkable rounding of the liver was noted in the androgen treatment groups.