Influence of vitamin B2 deficiency on polychlorinated biphenyls-induced liver lipid peroxides formation in rats.

The present study is carried out to explore whether the liver microsomal drug-metabolizing enzymes induced by PCB are associated with the PCB-induced liver lipid peroxide formation in rats. For this purpose, variations of the drug-metabolizing enzyme activities mediated by vitamin B2 deficiency were utilized. The administration of PCB to rats induced the liver microsomal cytochrome P-450 and vitamin B2 deficiency promoted the induction. The cytochrome b5 was also induced by PCB but no further induction by vitamin B2 deficiency was observed. The flavoenzyme, NADPH-cytochrome c reductase, was induced by PCB when the vitamin B2-supplemented PCB diet was fed to rats, but the activity of the enzyme was decreased by vitamin B2 deficiency and PCB further decreased the activity. The liver lipid peroxide levels increased in PCB groups with and without vitamin B2 compared with each PCB-free group, but the lipid peroxide level in vitamin B2-deficient PCB group was significantly lower than in vitamin B2-supplemented PCB group. From these results, the PCB-induced liver lipid peroxide formation was not necessarily related to the variations of the liver microsomal drug-metabolizing enzymes.