Higher activity of oxidative drug demethylation in the liver microsomes from dystrophic mouse.

The activities of NADPH-dependent oxidative demethylation of aminopyrine and other methyl compounds in the liver microsomes from dystrophic mice were found to be about 30% higher than those of the normal mice. Consumption of reduced pyridine nucleotides during the demethylation reactions was also significantly larger in the dystrophic mouse system than in the normal mouse system. The synergistic effect of further addition of NADH on the oxidative demethylation in the reaction system with NADPH, however, was not significant in either the normal or the dystrophic mouse system. The activities of NADPH-cytochrome c reductase and lipid peroxidation were also higher by about 30% in the dystrophic mouse than in the normal mouse, but the contents of cytochrome P-450 and phospholipids in the liver microsomes from normal and dystrophic mice were not appreciably different. The results suggest the possibility that the progressive muscular dystrophy may involve abnormal features in not only muscle but also liver and other tissues.