Androgen receptor localization in the human prostate: demonstration of heterogeneity using a new method of steroid receptor autoradiography

We have used a novel receptor labeling and autoradiographic technique to identify the cell types in human benign prostatic hyperplasia (BPH) that contain androgen receptors, and we have found that androgen receptor localization is heterogeneous. Prostatic androgen receptors were labeled by incubating slide-mounted frozen tissue sections (10 micron thickness) with 3H]R1881 in vitro. Tissue sections labeled in this way were subjected to concurrent biochemical and autoradiographic analysis. Some of the sections were wiped from the slides for scintillation counting to validate that the procedure indeed measures total cellular androgen receptors of appropriate high affinity and androgen steroid specificity. Replicate labeled slide-mounted tissue sections were dried rapidly, apposed to dry emulsion-coated coverslips, and exposed in the dark for autoradiography. Autoradiograms were developed, fixed, and stained; silver grains were counted over nuclei or cytoplasm of epithelium or stroma to evaluate specific androgen receptor location. Autoradiographic analysis of human glandular BPH demonstrated androgen receptor localization almost exclusively in the epithelial nuclei, with little or none in the stroma. We anticipate that data obtained using this new method of steroid receptor autoradiography may provide fresh insight into the mechanism of hormonal regulation of the prostate.