Effect of prolactin on androgen metabolism by the guinea-pig sex accessory organs.

The in vitro actions of prolactin on the metabolism of testosterone by the guinea-pig liver and sex accessory organs have been investigated under a variety of conditions including various concentrations of ovine or bovine prolactin, addition of reduced nicotinamide adenine dinucleotide phosphatate (NADPH) or nicotinamide adenine dinucleotide (NAD) to incubation media and various lengths of incubations. Treatment of the epithelium and muscle of the guinea-pig seminal vesicle with NAD elicited a shift from normal reductive metabolism of testosterone toward oxidative metabolism. This shift toward oxidative metabolism of testosterone was particularly marked in the muscle of the guinea-pig seminal vesicle. Ovine prolactin was highly effective in inhibiting the reductive metabolism of testosterone by the sex accessory organs. This effect appeared primarily as a decrease in dihydrotestosterone formation and was noted in both the presence and absence of NADPH or NAD. Oxidized metabolites, androstenedione and androstandione, were apparently insensitive to prolactin treatment in vitro. Variations induced by prolactin in the concentrations of intracellular androgens may be important in either the normal or abnormal growth and function of male sex accessory organs.