TRANSCRIPTIONAL REGULATION OF DOG PROSTATE ARGININE ESTERASE GENE BY ANDROGENS

These studies were designed to define the molecular events involved in the modulation of dog prostate arginine esterase gene expression foll owing short castration intervals and androgen treatment. Arginine este rase enzymatic activity and protein levels decreased about 50% 24 h af ter castration. Thereafter, a more progressive decrease was observed, resulting in 2-4-fold lower levels in 12-day castrates than in the int act controls. Total prostatic arginine esterase mRNA levels slowly dec reased during the first five days after castration but more abruptly t hereafter and were about 150-fold lower in 12-day castrated animals. B y contrast, in isolated prostatic nuclei, levels of arginine esterase RNA precursors and mature transcripts rapidly fell following orchiecto my, with a 50-70% decrease 24 h after castration. Nuclear run-on exper iments confirmed that the latter effects were the result of decreased arginine esterase gene transcription. All these changes could be at le ast partially reversed by administration of testosterone cypionate. Fu rthermore, no striking modifications in the proportion of epithelial/s tromal cells in the prostatic tissue were observed following orchiecto my. These results show that castration and androgens exert very rapid effects on the gene expression of arginine esterase, and that the regu lation occurs at the transcriptional level.