Vitamin K1 as a modulator of benzo(a)pyrene metabolism as measured by in vitro metabolite formation and in vivo DNA-adduct formation.

ABSTRACT

Vitamin K1 (2-methyl-3-phytyl-1,4-napthoquinone) increases the microsomal metabolism of benzo(a)pyrene in rat liver microsomes in vitro. The increase is most marked in the 9,10 diol, 4,5 diol and 3-OH metabolites. The effect is seen at an in vitro concentration of 25 microM and disappears at higher concentrations of K1. 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 K1. These findings indicate a role for vitamin K1 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.