Fundamental studies of prostatic carcinoma

Model-relapsed prostatic carcinoma (PC) was transplanted for generations to castrated rats. Donryu rats aged 49 days were castrated and, 24 hrs later, PC was implanted into the ventral prostate. Eight days later, antiandrogen (AA560;150μg), estrogen (EE3ME ; 20μg) and testosterone propionate (TP ; 150 μg) were injected s.c. once per day for 11 days, respectively. Twenty-four hrs after the final injection, rats were decapitated and then steroid hormones in adrenal and plasma analyzed with HPLC. It is clear that treatment with antiandrogen or estrogen to model cancer in relapsed prostatic cancer-bearing rats was ineffective. Consequently, tumor weights could not change in evidence. However, it should be noted that androgen levels originating in adrenal cortex were significantly increased. Especially, the testosterone level was higher than level of concentration in blood when given exogenous administrations. These results suggest that therapeutic usage of endocrine approaches is ineffective in relapsed prostatic cancer and this led to an indispensable role in human relapsed prostatic carcinoma. The problem of the adrenal androgen induction still remains.