5α-Metabolism in Finasteride-Treated Subjects and Male Pseudohermaphrodites with Inherited 5α-Reductase Deficiency

This study examined the effects of finasteride, a 5α-reductase inhibitor, on male pseudohermaphrodites with inherited 5α-reductase deficiency and finasteride-treated subjects with benign prostatic hyperplasia (BPH). The results showed that finasteride decreased plasma dihydrotestosterone (DHT) levels in a dose-dependent manner, while plasma testosterone levels tended to rise with increasing doses of finasteride. The study also found that urinary metabolite ratios in finasteride-treated subjects were dose-dependent. The study suggests that a single gene codes for a single 5α-reductase enzyme with broad steroid metabolic specificity.