Evidence for the association between blood prolactin and androgen receptors in BPH

The purpose of this study was to investigate the relationship between prostatic androgen receptors and plasma prolactin and testosterone in patients with benign prostatic hyperplasia. Cytosolic and KCl extractable nuclear androgen receptors were measured in 22 patients and these were in turn correlated to the hormone concentrations in blood specimens taken on the morning before the day of operation. The mean +/- S.E.M. concentrations of cytoplasmic androgen receptors, KCl extractable nuclear androgen receptors, plasma testosterone and plasma prolactin were respectively 115 +/- 18 fmoles/gm. tissue, 198 +/- 40 fmoles/gm. tissue, 15.6 +/- 1.2 nmol./l. and 128 +/- 17 mU/l. Plasma prolactin was highly correlated with cytosolic androgen receptors (r = 0.784, p less than 0.01; no. = 15) though not with nuclear androgen receptors (r = 0.453, p greater than 0.05; no. = 15). However, when the androgen receptor levels were expressed as fmoles/mg. protein both cytosolic and nuclear levels were proportional to plasma prolactin (p less than 0.01 and p less than 0.02 for both the cytosolic and nuclear receptors respectively; no. = 15). There was no correlation between either cytosolic and nuclear androgen receptors and plasma testosterone levels. The results suggest that plasma prolactin may be involved in the regulation of androgen receptor content in the benign prostate.