Abstract
The transport of vitamin E (alpha-tocopherol) has been studied in the rat erythrocyte in vivo and in vitro. Uptake and efflux are independent of energy, but sensitive to temperature. Tocopherol is localized to the cell membrane. Rapid exchange takes place between erythrocytes and serum with an hourly fractional tocopherol efflux of 26%. The vitamin is transferred from the erythrocyte to the low density lipoproteins. These experiments indicate that tocopherol, like cholesterol, is a constituent of the erythrocyte membrane which is in dynamic equilibrium with the corresponding plasma compound.