Androgen concentrations in epithelial and stromal cell nuclei of human benign prostatic hypertrophic tissues

Prostate tissues removed from patients with benign prostatic hypertrophy were separated into epithelial and stromal components and nuclei purified from these. The concentrations of testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha,17 beta-diol, 4-androstene-3,17-dione, 5 alpha-androstanedione and androsterone in pooled preparations of the purified nuclei were determined by radioimmunoassays after the purification of solvent steroid extracts by Lipidex-5000 column chromatography. The most abundant androgen measured was 5 alpha-dihydrotestosterone and it was significantly (P less than 0.05) more concentrated in the stromal nuclei than in the epithelial nuclei. The mean concentration of androsterone was also significantly (P less than 0.05) greater in the stromal nuclei whereas that of testosterone was equal in the two nuclear types. The concentrations of 5 alpha-androstane-3 alpha,17 beta-diol, 4-androstene-3,17-dione and 5 alpha-androstanedione were below the sensitivity limits of the assays in the majority of cases, but the results indicated that when detectable the first two were more concentrated in the stromal than the epithelial nuclei. The results emphasize the importance of the prostatic stroma in androgen metabolism, and the relative concentrations of 5 alpha-dihydrotestosterone and testosterone indicated identical 5 alpha-reductase activities in the nuclei in comparison with respective whole cell epithelial and stromal preparations. 5 alpha-Dihydrotestosterone concentrations were clearly higher than the nuclear androgen receptor levels previously reported from this laboratory.