Response to Letter: “Characteristics of Men Who Report Persistent Sexual Symptoms After Finasteride Use for Hair Loss”

摘要

We thank Santmann for his comments on our article. We agree with Santmann that the steroid 5α reductase activity is higher in the genital skin than in the nongenital skin. However, our inferences were based on multiple lines of evidence (1), not just on the gene expression patterns in the nongenital skin. Serum 5α dihydrotestosterone levels, testosterone to 5α dihydrotestosterone ratios, and circulating markers of tissue testosterone metabolism through the steroid 5α reductase pathway—5α-androstane-3α, 17β-diol glucuronide, and 5α-androstane-3α, 3β-diol glucuronide levels and the ratio of androsterone glucuronide to etiocholanolone glucuronide—were similar among symptomatic finasteride users and nonusers, providing no evidence of persistent inhibition of peripheral SRD5A activity by prior finasteride use. The nucleotide sequences of the androgen receptor, SRD5A1, and SRD5A2 genes did not reveal any...