Hepatic microsomal p-nitroanisole O-demethylase. Effects of chlordecone or mirex induction in male and female rats.

The effects of chlordecone (CD) or mirex treatment on the hepatic microsomal monooxygenase system of male and female rats were investigated, and kinetic parameters (apparent Vmax and apparent Km) for p-nitroanisole O-demethylase were studied in detail. Both pesticides elevated the levels of cytochrome P-450 in a time- and dose-dependent manner. The maximum rate of p-nitroanisole metabolism in males was increased about 100 and 50% and the apparent Km was elevated about 40- and 18-fold by CD and mirex respectively. p-Nitroanisole metabolism in females was reduced slightly by treatment with either agent, and the apparent Km was increased about 14-fold by CD but was relatively unaffected by mirex treatment.