916 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS

HUMAN HAIR FOLLICLES 917 HAl RY ARI[A TRANSIT I ONAL BALDNESS AREA Figure 6. •chematic representation of hair follicle distributions in hairy, transitional, and bald scalp regions follicles per unit of surface, an indcation that common baldness is caused by a metamorphosis of terminal into veilus-type follicles and consequent quiescence. Thus, the histological characteristics in the stump-tailed macaque coincide with those in human common baldness. Our second approach to the study of common baldness was to com- pare the metabolic capacities of hair follicles in human and monkey scalps, and to establish certain biochemical criteria (37). We were unable to follow the overall glucose metabolism of the monkey follicle because the plucking method used to obtain human hair follicles did not work well on monkeys. Accordingly, using Lowry's microtechnique (18, 20), we concentrated on the enzyme assays of hair follicles. Since enzyme activities differ considerably in different regions, even of the same type of hair follicles, it is difficult to compare them in the various types of hair follicles (telogen, veilus-type anagen, and terminal anagen). For example, enzyme activities are higher in the bulb portion than in the sheath epithelium of the anagen hair follicle. Therefore, it is necessary to specify not only the stage of the hair follicles but also the intrafollicular regions. Aware of these complexities, we compared the enzyme activities of the bald and hairy scalp (Table VIII). Veilus follicles from the bald frontal scalp and terminal anagen follicles from the hairy scalp showed about the same enzyme activities. Thus, as long as hair follicles con-