ANDROGEN BINDING-SITES ON NUCLEAR MATRIX OF NORMAL AND HYPERPLASTIC HUMAN-PROSTATE

To further characterize human prostatic androgen receptor, nuclei were isolated from normal prostate (n = 3) and benign prostatic hyperplasia [BPH] specimens (n = 10). High ionic strength (0.6 M KCl) treatment of nuclei released nuclear extractable androgen receptor and DNase I digestion then yielded nuclear matrices. Androgen receptor was quantified in the nuclear extract and nuclear matrix preparations by Scatchard analysis of specific R1881 [methyltrienolone] binding. Only 1 of the 3 normal tissues had extractable androgen receptor (113 fmol/g of tissue), while the mean concentration of extractable androgen receptor for BPH was 189 fmol/g of tissue. The mean concentrations of matrix-bound androgen receptor were 325 fmol/g of tissue and 548 fmol/g of tissue for normal and hyperplastic prostate, respectively. The androgen binding sites on nuclear matrix may represent the functional intranuclear androgen receptor and a characterization of these sites may provide an understanding of the etiology of BPH.