The distribution of 5 alpha-reductase and 3 alpha(beta)-hydroxysteroid dehydrogenase activities in the hyperplastic human prostate gland.

This study examines the distribution of 5 alpha-reductase and 3 alpha(beta)-hydroxysteroid dehydrogenase activities throughout the intact hyperplastic prostate gland and relate these measurements to the fibromuscular/epithelial composition and to the gross glandular morphology. The relative capacities of the stroma and epithelium to metabolize testosterone and dihydrotestosterone were also examined. The results indicate that under optimum reaction conditions an uneven distribution of 5 alpha-reductase and 3 alpha(beta)-hydroxysteroid dehydrogenase could be measured across the prostate. These regional variations reflect true differences in metabolic activity and were independent of any morphological changes: caution is therefore advised when interpreting hormonal metabolic data obtained from single sampling of the gland. Our investigations also suggest that the capacity to metabolize testosterone was evenly distributed between stroma and epithelium and that both tissue components are primary sites for 5 alpha-reductase activity. The reductive 3 alpha(beta)-hydroxysteroid dehydrogenase was also found in both tissue types but the mean stromal activity was marginally higher than the levels measured in the epithelium.