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

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 $\text{1}\text{12}\text{, 1, 3, 10}\text{and}\text{20}\text{days}$ 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 $\text{1}\text{12}\text{day}$ 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.