[Activity of 5 alpha-reductase in human hyperplastic prostates].

To Study the relationship between the activity of 5 alpha-reductase and benign hyperplastic prostate (BPH), we have measured the T and dihydrotestosterone (DHT) contents and the specific activity of this enzyme in mechanically separated stroma and epithelium and in both the nucleus and cytoplasm from 20 cases of BPH and 7 cases of normal human prostate. The results were as follows: (1) The content of DHT in the BPH group was about 3 times higher than that in the N group. (2) The Michaelis constant (Km) of 5 alpha-reductase in both the stroma and epithelium was similar. (3) The specific activity of the enzyme in the stroma was higher than that in the epithelium, and in the BPH group, increased activity was found in the tissue or stroma but not in the epithelium. The activity was predominant in the nucleus. So our experiment supports that the elevation of the activity of 5 alpha-reductase may be related to the pathogenesis of human BPH.