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 (no. = 3) and benign prostatic hyperplasia specimens (no. = 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 binding. Only 1 of the 3 normal tissues had extractable androgen receptor (113 fmol. per gm. of tissue) while the mean concentration of extractable androgen receptor for BPH was 189 fmol. per gm. of tissue. The mean concentrations of matrix-bound androgen receptor were 325 fmol. per gm. of tissue and 548 fmol. per gm. 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.