Status of Drug-Metabolizing Enzymes after Treatment of Fat-Deficient Mice with N-Nitrosodiethylamine

Dietary deprivation of fat in male Swiss mice for 6 weeks resulted in a decrease in cytochrome c-reductase (Cyt. c-red.) activity without alteration of the activities of arylhydrocarbon hydroxylase (AHH), aminopyrene demethylase (APD), and cytochrome P-450 (Cyt. P-450) in the liver, whereas levels of glutathione-S-transferase (GST) and reduced glutathione (GSH) were significantly increased by fat-free diet feeding. Following N-nitrosodiethylamine (NDEA) administration, AHH, APD, and Cyt.P-450 significantly declined, whereas GST and GSH were stimulated in the liver of control as well as fat-deficient mice. NDEA treatment decreased the activities of AHH and APD, and increased the GST activity in the lungs of fat-deficient mice only. The higher levels of GST and/or GSH in fat deficiency may have a protective role in chemical carcinogenesis.