Effect of endocrine manipulations on the levels of cytosolic and nuclear receptors for androgens in dog prostate.

Cytosolic and nuclear androgen receptor levels were determined in dog prostates after castration and after treatment with steroids. The cytosolic androgen receptor levels 1, 5, and 13 days after castration were reduced to 32, 47, and 34 per cent of intact dog levels. We also initiated steroid treatments immediately after castration. The administration three times weekly of either dihydrotestosterone, 5 alpha-androstane-2 alpha, 17 beta-diol (3 alpha-diol), or of a combination of 3 alpha-diol and estradiol resulted after 13 days in a 2 fold increase of cytosolic androgen receptors relative to intact untreated dogs. Androgen receptor levels in 0.5 M KCl nuclear extracts were significantly (P less than 0.01) increased in spontaneously hyperplastic prostates relative to normal prostates. They were also significantly (P less than 0.05) increased in dogs treated with either dihydrotestosterone, 3 alpha-diol, or with a combination of 3 alpha-diol and estradiol but were highly depressed after castration. These results suggest that experimental prostatic hyperplasia produced by the injection of androgens probably occurs via increased androgen receptor levels.