Hormonal activation of the adenylyl cyclases of the rat and human prostate gland

Abstract

The rat ventral prostate and the human hyperplastic prostate contain adenylyl cyclases which can be activated by a variety of neurotransmittors, including vasoactive intestinal peptide (VIP), β₂ adrenergic agonists, and dopamine. In both species the response to VIP was predominantly localized to the epithelial fraction. In the human tissue activation of the enzyme could also be achieved with prostaglandin E₁ (PGE₁) and an α₂ adrenergic agonist both associated with the stromal compartment. Castration in the rat caused a marked reduction in the basal activity of the enzyme and the maximal level of the hormone-stimulated response per cell (per mg DNA), but had only minor effects on the pattern of activation when expressed per mg membrane protein. Androgen treatment (dihydrotestos-terone propionate, 2.5 mg/day) prevented the castration effects. Estrogen treatment (estradiol benzoate, 125 μg/day) could not prevent the castrational changes but maintained enzyme activity at a level above that of the castrate. There were no major qualitative differences in the pattern of activation of the cyclase between the different lobes of the rat prostate and the seminal vesicle.