Regeneration of vitamin E in rat polymorphonuclear leucocytes.

The objectives of this study were to determine whether the recycling of tocopherol occurs in elicited rat polymorphonuclear leukocytes and if so, whether the recycling process is enzymic or chemical. When incubated with hemoglobin, tocopherol was oxidized in cell homogenates in a time- and concentration-dependent manner. The oxidized tocopherol could be regenerated by addition of ascorbate, glutathione or nordihydroguaiaretic acid. Time course studies showed a rapid regeneration of tocopherol which peaked at 1 min after the addition of reductants. Determination of the regeneration reaction in the presence of CHCl3 and MeOH indicated that under these enzyme-denaturing conditions, a considerable amount of tocopherol was still regenerated, suggesting that the regeneration reaction is predominantly a chemical reaction. This study provided direct evidence from mass analysis that oxidized vitamin E can be regenerated by cellular water-soluble reductants such as ascorbate and glutathione.