Effects of androgen on alpha- and beta-adrenergic receptors in membranes from the rat seminal vesicle.

The effects of castration and androgen-replacement on adrenergic receptors in membranes from the rat seminal vesicle were studied. Membranes from seminal vesicles showed saturable and high-affinity binding sites for the beta-adrenergic receptor antagonist, 3H]dihydroalprenolol (3H]DHA), and the alpha 1-adrenergic receptor antagonist, 3H]prazosin. Castration markedly reduced beta-adrenergic receptors with decreasing the effect of GTP modulating the receptor-ligand affinity, suggesting defects in both the receptor per se and the guanine-nucleotides-regulating mechanism after castration. In contrast, castration increased alpha 1-adrenergic receptors and androgen-replacement reversed this change. The effects of GTP decreasing the alpha 1-receptor binding affinity to the radioligand were observed to a similar extent in the castrated and control membranes. These results demonstrate an inverse regulation by androgen on beta- and alpha 1-adrenergic receptors in membranes of the rat seminal vesicle.