Testosterone metabolism in androgen target tissues of immature Wistar male rats was studied after the injection of ovine PRL (oPRL) or after changes in PRL levels induced by the administration of dopaminergic agonists or antagonists. Treatment with oPRL (500 μg/rat-day) for 10 days, starting on day 30 of age, caused a significant increase in testes and sex accessory organ weights and a concomitant augmentation in prostatic 5α-reductase activity. This effect, however, was not observed in epididymis and seminiferous tubules (ST). Daily administration of bromocriptine (3 mg/kg BW) using the same injection schedule suppressed endogenous PRL without altering serum LH levels. Testis and sex accessory organ weights and serum 5α-androstane-3α,17β-diol levels were reduced in the animals treated with this dopaminergic agonist. These changes were associated with a significant decrease in 5α-reductase activity in both prostate gland and ST. Treatment with the dopaminergic antagonist sulpiride (43 mg/kg BW) during the...