Uptake, storage and excretion of chylomicra-bound 3H-α-tocopherol by the skin of the rat

Abstract

Tritium- -tocopherol was incorporated into chylomicra by feeding dl-α-(5 methyl 3H)-tocopherol to rats with thoracic duct cannulae. Tritium α-tocopherol in chylomicra, isolated by flotation through 0.85% NaCl, was injected intravenously into rats and distribution of radioactivity was followed in skin, viscera and carcass. Label measured at 1 12 , 1, 3, 10 and 20 days following injection demonstrated a rapid uptake and prolonged retention in skin compared to viscera and carcass. In fact, relative distribution in skin increased from an average of 10.3% at 1 12 day to 40.1% of the recovered dose at 20 days. Also, the uptake of isotope by skin, expressed as 3H dpm/g lipid, markedly exceeded that of epididymal fat suggesting a preferential distribution to cutaneous tissue. Significant radioactivity was found on the skin surface and hair following injection of 3H-α-tocopherol demonstrating the excretion or secretion of vitamin E compound(s) by the skin.