Aromatization of androstenedione to estrogen by benign prostatic hyperplasia, prostate cancer and expressed prostatic secretions.

Human prostatic tissue and expressed prostatic secretions (EPS) from patients with benign prostatic hyperplasia (BPH) and prostate cancer were incubated with (1 beta 3H) androstenedione. The extent of aromatization was determined by measuring the transfer of 3H from the 1 beta position into water. The amount of 3H2O recovered corresponds to the estrogens formed. Tissue from 5 patients with BPH yielded 2.13 (+/- 1.05) pmol/mg protein/h while the EPS from the same patients yielded 727 fmol/mg protein/h. In patients with prostate cancer the mean formation of estrogens was 388 fmol/mg protein/h (+/- 75). 4-hydroxy-androstenedione, an aromatase inhibitor, successfully inhibited aromatization in BPH and prostate cancer 53-98%.