[Androgen and estrogen metabolism in human benign prostatic hyperplasia (BPH)]

Among all androgen metabolizing enzymes within the human prostate 5 alpha-reductase is the most powerful one. In the epithelium its activity decreases with age, while in the stroma it remains constant over the whole age range. Thus, in older prostates with benign hyperplasia the activity of 5 alpha-reductase is almost the same in both compartments. The same holds true for the DHT content, being highest in the epithelium of prostates from young men. With age it decreases to levels similar to those in the stroma. In contrast to DHT, estrogens are increasingly accumulated in the stroma with advancing age, while in the epithelium the estrogen level remains constant over the whole age range. The age-dependent decrease of the DHT level in the epithelium and the increase of the estrogen level in the stroma lead to a significant increase of the estrogen/androgen ratio. This could be of pathobiological importance for BPH development.