Conversion of Carotene to Vitamin A by Sebaceous Glands

Abstract

Recently, we demonstrated the conversion of carotene to vitamin A by the cells of sebaceous glands.¹The carotene, in the original carrot oil, was prepared as a water-solubilized suspension. It was injected intradermally. Upon histologic examination by fluorescent microscopy, the injected carotene was identified within the dermis by its bright yellow-gold color; the derived vitamin A was identified by its characteristic green fading fluorescence.² A part of the injected carotene was concentrated exclusively by the cells of the sebaceous glands; it was not concentrated by any other cells of the skin or its appendages. Subsequently, within minutes, detectable concentrations of vitamin A were visualized within the same sebaceous cells and especially within the sebum at the neck of the gland, in the hair follicle, and upon the skin surface. Normally, neither carotene nor vitamin A are detectable in these sites,^2-4probably be