Effect of dietary protein, dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) on hepatic microsomal enzyme activity in rats.

1. Albino rats were fed on diets containing 30, 120 or 200 g protein/kg with or without the incorporation of dichlorodiphenyltrichloroethane (DDT) or hexachlorocyclohexane (HCH) at 100 mg/kg diet for 4 weeks. 2. The activities of the liver microsomal enzymes NADPH-cytochrome reductase (EC 1.6.2.4), flavoprotein-linked monooxygenase (EC 1.14.14.1) and O-demethylase were significantly greater in animals fed on 120 and 200 g protein/kg diet compared with those fed on 30 g protein/kg diet. 3. The inclusion of DDT or HCH at all protein intakes led to further significant rises in microsomal enzyme activities but the increases were much greater for animals receiving the 120 and 200 g protein/kg diets than for those receiving the 30 g protein/kg diet. 4. The results imply that detoxification of DDT or HCH was carried out more effectively at the higher protein intakes.