EFFECTS OF ANDROGEN AND ESTROGEN ON DNA SYNTHESIS IN IMMATURE RAT PROSTATE

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We investigated the effects of testosterone propionate (T) and/or estradiol (E₂) on the activity of thymidine kinase (TK) and its isozymes and the incorporation of ³H-thymidine in the prostate of immature rats. The maximum activity of prostatic TK increased approximately 50 times the basal level 48hr after T administration. Puromycin and actinomycin D inhibited nearly 100% of the increase induced by T administration. The prostatic TK isozymes were separated into 3 types by DEAE-cellulose column chromatography, and the activity of the isozyme eluted with buffer alone was markedly increased in T-treated rats, and this isozyme was suggested to be involved in rapid DNA replication because its activity was not affected by deoxycytidine triphosphate (dCTP). The addition of E₂ quickened the induction of maximum TK activity due to T administration. Autoradiographic examination indicated that T alone induced marked DNA synthesis in prostatic epithelium, and E₂ plus T enhanced DNA synthesis synergistically.