Effect of prolactin and the anit-prolactin bromocriptin on the testosterone uptake and metabolism in androgen-sensitive and insensitive canine organs.

Prolactin promotes the growth and function of the prostate in low doses, whereas high doses or previous castration reduce this effect. The antiprolactin bromocriptin should reverse the prolactin action. In the castrated dog the highest accumulation of H3-testosterone given i.v. occurred in the prostate as compared with muscle, urethra, penis, liver and kidney. Prolactin pretreatment increased the radiosteroid uptake only in the liver. Converseley, bromocriptin suppressed the tracer incorporation into the liver, but increased prostatic accumulation. The highest testerone reduction occurred in the prostate of the untreated castrated dogs as compared with other organs. Prolactin suppressed 5 alpha -dihydrotestosterone formation but otherwise did not significantly influence testosterone turnover. Bromocriptin, however, stimulated dihydrotestosterone formation in the prostate and caused complete inhibition of hepatic testosterone reduction.