Conversion of Carotene to Vitamin A by Sebaceous Glands

Although the skin is characteristically modified in vitamin A deficiency states,1,2only insignificant amounts of carotene and vitamin A are present in normal skin and sebum,3,4and neither of these has been demonstrated even by the very sensitive fluorescent histologic techniques.5-7 Recently, Greenberg et al.8have reported an i. v. injectible carotene preparation (Endo 54118),*which is quickly (in minutes) and efficiently (20%-25%) converted to vitamin A by the liver and in lesser amounts by the lungs, adrenals, and spleen. We, therefore, injected this material into intradermal sites in man and in rats. Subsequently, biopsy samples were examined histologically for their vitamin A content (green fading fluorescent material) by fluorescent microscopy. Moderate amounts of vitamin A were demonstrable within 20 minutes of injection in the cells of the sebaceous glands, and in the sebum filling the hair follicles and spread upon the skin