Production rates of testosterone and of dihydrotestosterone in female pattern hair loss

Abstract

Production rates of testosterone (T) and of dihydrotestosterone (DHT) were determined in young women (n = 8, age, 23 to 40 years) with female-pattern hair loss using the stable isotope dilution technique and mass spectrometry. 1α,2α- d-testosterone and 2,3,4- 13C-dihydro-testosterone were infused for 10 hours at a dose of 2 μg/h each and blood samples were obtained at 20-minute intervals during the last 4 hours of the observation period. In the presence of normal metabolic clearance rates (MCRs), production rates of T were increased (9.4 ± 5.0 μg/h; normal, 4.3 ± 1.9 μg/h, P < .05). MCRs of DHT (8.0 ± 3.4 L/h; normal, 25.9 ± 12.3 L/h, P < .002) were subnormal in all women and the production rates of DHT were within or below the normal range (mean, 1.6 ± 0.6 μg/h; normal, 2.9 ± 1.1 μg/h, P < .02). Unlike men with male-pattern baldness, women with female-pattern baldness are characterized by increased production rates of T, but not of DHT. These results are compatible with the idea that 5α-reductase inhibition is of no therapeutical value in female-pattern baldness.