918 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS

HUMAN HAIR FOLLICLES 919 tinue to grow, regardless of type and size, the enzymes maintain their potential activities. From these data we were unable to establish an enzymatic criterion for baldness however, we did demonstrate that enzyme activities in the different types of hair follicles in man and in stump-tailed macaques are similar and of the same magnitude. This fact adds a biochemical rationale for the use of this monkey in the study of baldness. Although common baldness in man is closely related to genetic fac- tors, it is triggered by testosterone. In stump-tailed macaques also baldness is caused by the male hormone. Therefore, we assume that testosterone metabolism differs in the hair follicles from bald and hairy areas. Using microchemical methods, we tested our theory by comparing the uptake rates of labeled testosterone and its catabolism in vitro in follicles from bald and nonbald areas of stump-tailed macaques. The microprocedures (38) used were as follows: Fresh thin pieces of scalp skin from monkeys were incubated with testosterone-aH, washed with nonlabeled carrier testosterone, frozen-sectioned, and frozen-dried under vacuum. From the frozen-dried slices, sections of the bulb and sheath portions of both anagen (terminal and veilus) and telogen hair follicles were microdissected and subjected to microscale analysis for testosterone and its metabolites by the method of Pearlman and Pearl- man (39) as modified by Resko et al. (40). After separation of con- jugated radiometabolites, the unconjugated (free) radiometabolites were separated on silica gel thin-layer plates in benzene/ethyl acetate (6/4, v/v). Most of the radioactivity on the chromatogram was associated with areas that had the mobility of testosterone (Zone A) and andro- stenedione (Zone B). Because various metabolites of testosterone have mobilities on this thin-layer system similar to those of testosterone and androstenedione, the terms Zones A and B were adopted. The incorporation of testosterone and its catabolism in different types and parts of hair follicles from different skin regions are sum- marized in Table IX. The production rate of Zone A material is less in follicles from bald areas, whereas the production rate of Zone B material is much faster in follicles from bald areas. Consequently, the ratio of Zone B/Zone A material is less than one in hair follicles from hairy regions and more than one in hair follicles from bald areas. In a previous study it was found that the enzyme activities of carbo- hydrate metabolism were nearly the same in both terminal and veilus-