"Dopa Oxidase" in Melanocytes of X-Irradiated Quiescent (Telogen) Hair Follicles

Abstract

"Dopa oxidase" activity was found to be absent in melanocytes of telogen hair follicles of non-irradiated C3H mice. Following partial-body exposure to 200 r/ week of X-radiation for 3 or 4 weeks, numerous dopa reactive dendritic cells were observed in the epithelial germ regions of irradiated quiescent hair follicles. Cells of the dermal papillae in irradiated and nonirradiated telogen hair follicles failed to exhibit "dopa oxidase" activity. The results thus support the view that melanocytes associated with hair pigmentation normally are restricted to the epithelial germ regions of hair follicles during telogen stage of the hair growth cycle.