Alpha]‐Tocopherol metabolism in human using tracer doses of 14C‐RRR‐[alpha]‐Tocopheryl acetate and 14C‐all‐rac‐[alpha]‐Tocopheryl acetate

Abstract

The natural form of [alpha]-Tocopherol (RRR-) is a stereoisomer of the synthetic form (all-rac-). Because these forms differ in their in vivo kinetics, 14C labeled [alpha]-Tocopheryl acetate were used to discern the dose from the endogenous pool. This study has a crossover design conducted on a healthy male. A minute dose of 14C-RRR-[alpha]-Tocopheryl acetate (0.01821 [mu]mol with 101.5nCi 14C) was administered, followed by a 3 month washout period, and then administration of the 14C-all-rac-[alpha]-tocopheryl acetate (0.001667 [mu]mol with 99.98nCi14C) to the same subject. Blood was collected for 63d, urine for 8d, and feces for up to 7d post dose. All neat samples were analyzed for 14C content by using Accelerated Mass Spectrometry. Each plasma sample was further separated into lipoprotein fractions by using a novel method developed by Hosken et al 2005. This method separates lipoprotein with a cesium-cadmium complex of EDTA in a single spin. Also, the addition of a fluorescence probe allowed for digital imaging of lipoprotein layers. After each lipoprotein fractions are separated, individual fractions were put though a RP-HPLC. Work was supported by DK R01-48307