To investigate the relation between androgens and hair growth, testosterone-1,2-3H metabolism was assessed under standardized conditions in growing (anagen) and resting (telogen) hair roots from 10 anatomical sites from 4 women and 14 men, 6 of whom had varying degrees of male pattern baldness. A micromethod was developed to quantitate androgen metabolism in only a few hair roots. In all hairs examined, 5α-reduced and 17-ketosteroids were the major metabolites of testosterone. No significant relation was found between androgen-mediated growth of hair and the capacity to form 5α-metabolites, e.g., scalp hair of women performed 5α-reduction to approximately the same degree as beard hair from men. The formation of 17-ketometabolites was decreased in telogen hairs from all body sites, whereas the formation of dihydrotestosterone was decreased in telogen hairs only from the scalp. In general a higher formation of 5α-reduced metabolites and 17-ketosteroid metabolites was observed at all sites of the scalp of bald men as compared to hair obtained from the corresponding sites of women and nonbalding men, and a significantly higher rate of metabolism was found at the frontal area of the bald men. It is not clear at present whether these changes are secondary to the balding process or are related causally to the hair loss. On the basis of these studies it is concluded that regional differences in androgen-mediated hair growth cannot be the result of variations in testosterone metabolism in the hair follicles.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical