The role of 5-alpha reductase inhibitors in prostate pathophysiology: Is there an additional advantage to inhibition of type 1 isoenzyme?

Abstract

Normal growth and function of the prostate are contingent on the reductionof testosterone to dihydrotestosterone (DHT) by 5-alpha reductase(5-AR) enzymes types 1 and 2. It has been theorized that an overabundanceof DHT may be implicated in the pathogenesis of both benign prostatic hyperplasia(BPH) and prostate cancer. Inhibitors of 5-AR such as dutasteride andfinasteride may therefore have an important role in the prevention and treatmentof BPH and prostate cancer. Dutasteride provides greater suppression ofDHT than finasteride, thereby underlying the hypothesis that inhibition of bothtype 1 and type 2 would provide correspondingly greater protection than inhibitionof type 2 alone. We review the potential significance of the 5-ARinhibitors in reducing the risk of prostate cancer according to the basic biologyof prostate disease