[Role of lipid peroxidation in the regulation of liver microsomal monooxygenase activity in homoiothermic animals exposed to cold].

The reaction rates of N-demethylation of aminopyrine, p-hydroxylation of aniline and hydroxylation of 3,4-benzo(a)pyrene in liver microsomes were determined in rats exposed to severe cold (-7 degrees C) for a long time (8 days). The data obtained demonstrate the decreased activities of 3,4-benzo(a)pyrene hydroxylase and aniline hydroxylase. There were no distinct alterations in aminopyrine N-demethylase activity. The increased levels of NADPH- and ascorbate-dependent microsomal lipid peroxidation together with impairment of the soluble antioxidant glutathione system are considered in animals exposed to cold as a possible mechanism of monooxygenase activity deterioration in liver microsomes.