Possible Interaction between Vitamin E and K Metabolism

Abstract

To elucidate the effects of vitamin E on vitamin K metabolism, we determined the effect of tocopherol intake on vitamin K concentrations in rats fed phylloquinone (PK). Dietary intake of α-tocopherol (αT) for 6 weeks decreased PK concentrations in extrahepatic tissues but not in liver in rats. Oral administration of αT by gavage decreased PK concentrations in some extrahepatic tissues but not in liver. Tocopherol hydroxylase, the rate-limiting enzyme of tocopherol catabolism, also catalyzed PK hydroxylation, the first step of PK catabolism. We determined the effect of sesame lignan, an inhibitor of tocopherol catabolism, on vitamin K concentrations in rats. Dietary intake of sesamin for 7 days increased PK, menaquinone-4, and tocopherol concentrations in rat liver. These data demonstrate that metabolic change of tocopherol influences PK concentrations.