McCoy G D, DeMarco G J, Biaglow J A
Biochem Pharmacol. 1985 Dec 15;34(24):4263-7. doi: 10.1016/0006-2952(85)90282-5.
The effects of two different methods of administering ethanol to hamsters on liver microsomal cytochrome levels and the activities of ethoxyresorufin O-deethylase and p-nitroanisole O-demethylase have been examined. Administration of ethanol in liquid diets resulted in enhanced levels of cytochrome P-450, NADPH-supported aniline hydroxylase (Form I), and both NADPH- and NADH-supported p-nitroanisole O-demethylase. NADH-ferricyanide reductase was also increased. No change in NADPH-cytochrome c reductase or in the NADPH-supported rate of ethoxyresorufin O-deethylase was observed. In contrast, both NADH-supported ethoxyresorufin O-deethylase and cytochrome b5 levels were decreased. Administration of ethanol in the drinking water to chow-fed animals had no effect on total cytochrome P-450 levels; however, the rates of NADPH-supported aniline hydroxylase (Form I) and p-nitroanisole O-demethylase activity were increased. No changes in NADPH-cytochrome c reductase, NADH-ferricyanide reductase, or NADH-supported p-nitroanisole O-demethylase activity were noted. Cytochrome b5 levels were decreased as were both the NADPH- and NADH-supported rates of ethoxyresorufin O-deethylase. These data suggest that chronic consumption of ethanol by hamsters either in liquid diet form or as ethanol-water solutions to chow-fed animals lowers cytochrome b5 levels. When cytochrome b5 levels are lowered and total chromosome P-450 levels remain unchanged, the NADPH-supported rate of microsomal O-dealkylation of ethoxyresorufin is decreased. These data suggest that cytochrome b5 participates in the NADPH-supported microsomal O-dealkylation of ethoxyresorufin.
