Prostatic expression of human 5alpha-reductase type 2 during finasteride therapy: a randomized, double-blind, placebo-controlled study.

This study was aimed at exploring the effect of finasteride, a non-steroidal competitive inhibitor of the enzyme 5alpha-reductase, on 5alpha-reductase type 2 at the mRNA level in human prostate, using an in situ hybridization technique. After randomization, 10 men with benign prostatic hyperplasia (BPH) received oral finasteride (5 mg daily) and five men with BPH received placebo daily. Careful clinical examination was carried out and 2 biopsy samples were taken transrectally before the treatment and after 3, 6, and 12 months of treatment. In situ hybridization was carried out and expression of 5alpha-reductase type 2 mRNA was measured. The results showed that finasteride treatment had no permanent effect on expression of 5alpha-reductase type 2 in prostatic epithelium, compared with placebo treatment. Expression varied during treatment, but there was no clear tendency in this expression. The signal was localized in the epithelial cells. We conclude that finasteride treatment had no clear effect on human 5alpha-reductase type 2 expression in the prostate.