Comparative changes in plasma and RBC .ALPHA.-tocopherol after administration of dl-.ALPHA.-tocopheryl acetate and d-.ALPHA.-tocopherol.

Abstract

Changes in plasma and RBC [red blood cell] .alpha.-tocopherol after i.v. and oral administration of dl-.alpha.-tocopheryl acetate were investigated using vitamin E-deficient rats and were compared with those following the administration of d-.alpha.-tocopherol, which is the most active and natural form of tocopherol. I.v. administration: by administration of dl-tocopheryl acetate, the elevated plasma tocopherol levels were higher at 6 h than those elevated by d-tocopherol, but the RBC tocopherol was lower 6 h after the infusion of dl-tocopheryl acetate than after d-tocopherol infusion. The tocopheryl acetate incorporated in the RBC remained for 24 h after the administration of tocopheryl acetate, the acetate then becoming undetectable in plasma. Oral administration: The tocopherol elevated in plasma and RBC was only the .alpha.-form and not tocopheryl acetate. In plasma and RBC, tocopherol levels were higher after the administration of d-tocopherol than after dl-tocopheryl acetate administration; more was found in RBC.