Dose- and time-dependent effects of menadione on enzymes of xenobiotic metabolism in rat liver.

We studied the effect of synthetic vitamin K analogue menadione on enzymes of xenobiotic metabolism in rat liver (total content of cytochrome P450 and catalytic activities of CYP1A1/2, CYP2B1, CYP2C, NADPH-cytochrome P450 reductase, and glutathione S-transferase). Menadione induced phase I and II enzymes for metabolism of xenobiotics, drugs, and procarcinogens. The effect of menadione depended on its dose and duration of treatment.