Immunohistochemical and Autoradiographic Findings Suggest Minoxidil Is Not Localized in Specific Cells of Vibrissa, Pelage, or Scalp Follicles

The study investigated the localization of minoxidil in hair follicles using immunohistochemistry and autoradiography. It was found that minoxidil-immunoreactivity was associated with certain cells in cultured vibrissa follicles of neonatal mice, but this was likely non-specific. Further tests showed minoxidil-immunoreactivity in various tissues, including non-haired organs, suggesting non-specific binding. In vivo and in vitro studies demonstrated that tritiated minoxidil bound only to melanin granules in pigmented follicles, which was also considered non-specific due to melanin's known ability to accumulate various drugs. The study concluded that minoxidil was not specifically localized in any cells of whisker, pelage, or scalp follicles under the experimental conditions.