922 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS In order to prove the proposed hypothesis, each step must be meticu- lously studied, and clearly many experiments remain to be performed. Our data accumulated in the past three years have just begun to eluci- date a phase of the molecular mechanisms related to the etiology of alo- pecia. The roles played by 5o•-dihydrotestosterone and adenyl cyclase ap- pear to be highly significant in this complex mechanism. (Received June 18, 1970) REFERENCES (i) Rogers, G. E., Structural and Biochemical Features of the Hair Follicles, in Montagna, W., and Lobitz, %f. C., Jr., The Epidermis, Academic Press, New York, 1964, pp. 179-236. (2) Matoltsy, A. G., Soluble Prekeratin, in Lyne, A. G., and Short, B. F., Biology of the Skin and Hair Growth, American Elsevier Publishing Co., Inc., New York, 1965, pp. 291-305. (3) Crounse, R. G., An Approach to a Common Keratin Sub-Unit, Ibid., pp. 307-12. (4) Rogers, G. E., and Clarke, R. M., An Approach to the Investigation o[ Protein Bio- synthesis in Hair Follicles, Ibid., pp. 329-43. (5) Gillespie, J. M., The High-Sulphur Proteins of Normal and Aberrant Keratins, Ibid., pp. 377-98. (6) Montagna, ¾V., Gonsiderazioni sulla filogenesi del cuoico capelluto, Mineroa Dermatol., 38, Suppl. No. 1,202-8 (1963). (7) Montagna, ¾V., Machida, H., and Perkins, E., The skin of primates. XXVIII. The stump-tail macaque, Amer. J. Phys. Anthropol, 24, 71-85 (1966). (8) Montagna, •'., and Uno, H., Baldness in nonhuman primates, .1. Sac. Cosmet. Chem., 19, 173-85 (1968). (9) Bullough, •'. S., and Laurence, E. B., The Miratic ,4ctivity of the Follicle, in Montagna. W., and Ellis, R.A., The Biology of Hair Growth, Academic Press, New York, 1958, pp. 171-87. (10) Van Scott, E. J., Reinertson, R. P., and Steinmuller, R., The growing hair roots of the human scalp and morphologic changes therein following amethopterin therapy, ]. Invest. Dermatol., 29, 197-204 (1957). (11) Adachi, K., and Uno. H., Glucose metabolism of growing and resting human hair follicles, Amer. J. Physiol., 215, 1234-9 (1968). (12) Adachi, K., and Uno, H., Some Metabolic Profiles of Human Hair Follicles, in Montagna, %', and Dobson, R. L., Hair Growth, Pergamon Press, Oxford and New York, 1969, pp. 511-34. (13) Uno, H., Adachi, K., and Montagna, W., Morphological and Biochemical Studies of Hair Follicle in Common Baldness of Stump-Tailed Macaque (Macaca speciosa), Ibid., pp. 221-45. (14) •'ood, H. G., Katz, J., and Landau, B. R., Estimation of pathways of carbohydrate metabolism, Biochem. Z., 338, 809-47 (1963). (15) Katz, .1., Landau, B. R., and Bartsch, G. E., The pentose cycle, triose phosphate isomerization, and lipagenesis in rat adipose tissue, J. Biol. ½hern., 241, 727-40 (1966). (16) Rognstad, R., and Katz, J., The balance of pyridine nucleotides and ATP in adipose tissue, Proc. Nat. Acad. Yci. U.S., 55, 1148-56 (1966).

HUMAN HAIR FOLLICLES 923 (17) Beatty, C. H., Peterson, R. D., and Bocek, R. M., Metabolism of red and white muscle fiber groups, Amer. J. Physiol. 204, 939-42 (1963). (18) Lowry, O. H., The quantitative histochemistry of the brain. Histological sampling, J. Histochem. Cytochertt., 1, 420-8 (1953). (19) Lowry, O. H., Roberts, N. R., Wu, M. L., Hixon, W. S., and Crawford, E. J., The quantitative histochemistry of brain. II. Enzyme measurements, J. Biol. Chem., 207, 19-37 (1954).' (20) Lowry, O. 'H., and Passonneau, J. v., The relationships between substrates and en- zymes of glycolysis in brain, Ibid., 239, 31-42 (1964). (21) Uno, H., Adachi, K., and Montagna, W., Glycogen contents of primate hair follicles, J. Invest. Dermatol., 51, 197-9 (1968). (22) Montagna, W., and Chase, H. B., Histology and cytochemistry of human skin. X. X-irradiation of the scalp, A ruer. J. A nat., 99, 415-46 (1956). (23) Adachi, K., Chow, D.C., and Rothman, S., Metabolism of glycogen in skin and the effect of radiation, Science, 135, 216-7 (1962). (24) Wotiz, H. H., Mescon, H., Doppel, H., and Lemon, H. M., The in vitro metabolism of testosterone by human skin, ]. Invest. Dermatol., 26, 113-20 (1956). (25) Gomez, E. C., and Hsia, S. L., In vitro metabolism of testosterone-4-•C and A •- androstene-3,17-dione-4-•C in human skin, Biochemistry, 7, 24-32 (1968). (26) Bruchovsky, N., and Wilson, J. D., Evidence that dihydrotestosterone is the active form of testosterone, Clin. Res., 16, 74 (1968). (27) Bruchovsky, N., and Wilson, J. D., The conversion of testosterone to 5 a-androstane-17/•- ol-3-one by rat prostate in vivo and in vitro, J. Biol. Chem., 243, 2012-21 (1968). (28) Bruchovsky, N., and Wilson, J. D., The intranuclear binding of testosterone and 5 a- androstan-17/•-ol-3-one by rat prostate, Ibid., 243, 5953-60 (1968). (29) Morris, J. M., and Mahesh, V. B., Further observations on the syndrome "Testicular Feminization," Amer. J. Obstet. Gynecol., 87, 731-48 (1963). (30) Strauss, J. S., and Pochi, P. E., Recent advances in androgen metabolism and their relation to the skin, Arch. Dermatol., 100, 621-36 (1969). (31) Lowry, O. H., Passonneau, J. v., Schultz, D. W., and Rock, M. K., The measurement of pyridine nucleotides by enzymatic cycling, ]. Biol. Chem., 236, 2746-55 (1961). (32) Butcher, R. W., Robinson, G. A., Hardman, J. G., and Sutherland, E. W., The Role of Cyclic AMP in Hormone Actions, in Weber, G., Advances in Enzyme Regulation, Per- gamon Press, Oxford, London, Edinburgh, New York, Toronto, Sydney, Paris, and Braunschweig, 1968, pp. 357-89. (33) Robinsoq, G. A., Butcher, R. W., and Sutherland, E. W., Cyclic AMP, in Boyer, P. D., Annual Review of Biochemistry, Annual Reviews, Inc., Palo Alto, Calif., 1968, Vol. 37, pp. 149-74. (34) Krishna, G., Weiss, B., and Brodie, B. B., A simple, sensitive inethod for the assay of adenyl cyclase, .l. Pharmacol. Exp. Ther., 163, 379-85 (1968•. (35) Tao, M., and Lipmann, F., Isolation of adenyl cyclase from Escherichia coli, Proc. Nat. Acad. Sci. U.S., 63, 86-92 (1969). (36) Uno, H., Allegra, F., Adachi, K., and Montagna, W., Studies of common baldness of the stumptailed macaque, I. Distribution of the hair follicles, J. Invest. Dermatol., 49, 288-96 (1967). (37) Uno, H., Adachi, K., Allergra, F., and Montagna, W., Studies of common baldness of the stumptailed macaque, II. Enzyme activities of carbohydrate metabolism in the hair follicles, Ibid., 51, 11-18 (1968). (38) Takashima, I., Adachi, K., and Montagna, W., Studies of common baldness of the stump- tailed macaque. IV. In vitro metabolism of testosterone in the hair follicles, Ibid., In press (1970).