The Conversion of Testosterone to 17β-Hydroxy-5α-androstan-3-one (Dihydrotestosterone) by Human Hair Follicles

Abstract

We demonstrated the conversion of testosterone-4-¹⁴C to dihydrotestosterone (17β-Phydroxy-5α-androstan-17-one), the tissue-active androgen, with 50–200 μg of freeze-dried human hair follicles plucked from various regions. All of the hair follicles thus far tested contained the 5α-reductase activity. Under optimal conditions, the 5α-reductase activity in growing hair follicles ranged from 10–20 nmoles/100 mg dry wt/hr. In the scalp, the growing follicles showed 3–8 times higher values than the resting. In other regions such as the beard, axilla, chest, pubis, arms and legs, the growing follicles showed nearly the same activities as those of the scalp or even higher, whereas the activities of the resting follicles varied considerably.