Steroid hormones and the pathogenesis of benign prostatic hyperplasia.

The pathogenesis of benign prostatic hyperplasia (BPH) is still poorly understood: there is, however, general acceptance that the condition is not premalignant and that it has an etiology distinct from that of cancer. Interest now focuses on the biochemistry of the target prostate cells and the propensity of the gland for uncontrolled growth. Dihydrotestosterone (DHT) is the active intracellular androgen formed from testosterone by 5 alpha-reductase. DHT concentrations appear a little higher in BPH tissue than in normal tissue, and there is no doubt that DHT-receptor complex modulates gene expression. Current studies suggest that DHT is essential but not sufficient for proliferation, and that other regulatory factors, including peptide growth factors, are prerequisite. The growth responsiveness of prostate tissue to androgens may be dependent on the balance between epithelial and stromal tissues, with biologic processes in the epithelium indirectly controlled by androgen-dependent mediators of stromal origin.