GENES REGULATED BY ANDROGEN IN THE RAT VENTRAL PROSTATE

Genes that are regulated by androgen in the prostate were studied in t he rat. Four of the less than 10 genes that are down-regulated by andr ogen in the ventral prostate of a 7-day castrated rat were identified; their mRNAs decayed with identical kinetics. Twenty-five of the estim ated 56 genes that are up-regulated by androgen in the castrated prost ate have been isolated. The up-regulated genes fall into two kinetic t ypes. Early genes are significantly up-regulated by 6.5 hr whereas the delayed genes respond mainly after 24 hr from the time of androgen re placement. These androgen-response genes are also regulated in the pro state by castration, indicating that these genes could play important roles in androgen-induced regrowth and/or castration-induced regressio n of the prostate during hormonal manipulation, A survey of the tissue specificity showed that the androgen-response gene expression program in the prostate is mainly prostate-specific. Total RNA Northern blot analysis detects the expression of about 16 up regulated genes and 3 d own-regulated genes in the prostate only. Four up-regulated genes and one down-regulated gene are regulated by androgen in both the prostate and seminal vesicles but not in other organs. The expression of the r emaining androgen-response genes is not limited to the prostate but is only responsive to androgen in the prostate. This survey of the andro gen-response gene expression program provides insights into the molecu lar and cellular mechanisms of androgen action in the prostate.