Baldness was induced by long-term injections of testosterone. Baldness in these animals is pre-determined, and only those parts of the scalp that normally become bald are affected by androgen even when transplanted in foreign sites. In vitro studies of the metabolism of testosterone by hair follicles and by the epidermis showed the same regional and age variation. The rate of total metabolism of testosterone was higher in frontal than in occipital areas, and was higher in younger than in adult animals. The ratio of metabolites to unmetabolized testosterone was higher in the frontal area. The amount of 5α-dihydrotestosterone was highest in the frontal scalp of young animals.
Takashima I, Montagna W. Studies of Common Baldness of the Stump-Tailed Macaque (Macaca speciosa)VI. The Effect of Testosterone on Common Baldness. Arch Dermatol. 1971;103(5):527-534. doi:10.1001/archderm.1971.04000170061017