Vitamin K 1 as a modulator of benzo(a)pyrene metabolism as measured by in vitro metabolite formation and in vivo DNA-adduct formation

Abstract

1. 1. Vitamin K 1 (2-methyl-3-phytyl-l,4-napthoquinone) increases the microsomal metabolism of benzo(a)pyrene in rat liver microsomes in vitro. 2. 2. The increase is most marked in the 9,10 diol, 4,5 diol and 3-OH metabolites. 3. 3. The effect is seen at an in vitro concentration of 25 μM and disappears at higher concentrations of K 1. 4. 4. The production of BP metabolite-DNA adducts in liver in vivo in ICR/Ha mice is reduced in dietary induced vitamin K deficient mice and this effect is reversed by vitamin K 1. 5. 5. These findings indicate a role for vitamin K 1 in the regulation of the microsomal mixed function oxidase system and suggest a reason for the low intracellular content and minimal body stores of this vitamin.