Conversion of Carotene to Vitamin A by Sebaceous Glands

The study demonstrates that sebaceous glands can convert carotene to vitamin A, as shown through fluorescent microscopy. Carotene, injected intradermally as a water-solubilized suspension, was identified in the dermis by its yellow-gold color, while the derived vitamin A was identified by its green fluorescence. The conversion occurred exclusively in sebaceous gland cells, with vitamin A concentrations appearing within minutes in the sebaceous cells, sebum, hair follicle, and skin surface. This conversion process is not typically detectable in these sites under normal conditions.