Increased levels of nuclear androgen receptors in hyperplastic prostate of aging men

Several publications indicate the dihydrotestosterone content of hyperplastic prostatic tissue from man and dog is increased. There is limited information concerning an abnormality in the androgen receptor content in this disorder. In men, we determined the androgen receptor concentration in cytosol, nuclei, the nuclear matrix, and nuclease solubilized salt extract fractions from benign prostatic hyperplasia (BPH) and normal prostate. Nine BPH cases (age 61 +/- 7, mean +/- SD) and seven controls (age 29 +/- 10.6) were compared. Prostates were obtained during autopsy performed within 12 h after death and frozen at -70 degrees C until analysis. Four grams of tissue were homogenized and centrifuged for separation of nuclei and cytosol. Androgen receptors were estimated with an improved assay procedure. The androgen receptor content per mg of DNA in whole nuclei and in the salt extract fraction (P less than 0.01 and less than 0.05 respectively) was higher in BPH cases than in controls. Cytosol did not show a significant difference. For both groups, receptors were undetectable in the nuclear matrix. We speculate that increased androgen receptor bound to chromatin of hyperplastic tissue may be causally related to the development of BPH in aging man.