Effects of oestrogen-induced hyperprolactinemia on the rat prostate

Exposure of intact rats to increasing doses of oestradiol-17 beta in the presence of a constant amount of exogenous androgen caused a dose-related increase in the concentration of zinc in the lateral lobes and a decrease in the levels of ventral lobe prolactin binding. These changes occurred concomitantly with a dose-dependent increase in plasma prolactin levels, and could not be obtained in hypophysectomized rats given the same steroid treatment. In the intact animals a dose-dependent decrease in the responsiveness of the prostaglandin E1-dependent adenylyl cyclase in the ventral lobe was observed, an effect which has earlier been shown to be prolactin mediated. The results indicate that oestrogen has indirect effects on specific parameters of prostate function by inducing a relative hyperprolactinemia. This model may be useful in studying effects of chronically and physiologically elevated levels of endogenous prolactin on the rat prostate.