The effect of phenobarbitone on cytoplasmic NADP-linked dehydrogenase activities in rat liver.
Phenobarbitone administered in drinking water (0.5 g/l) or by daily intraperitoneal injection (100 mg/kg body weight) consistently caused an elevation of hepatic NADP-linked malic enzyme in rats maintained on a pellet diet. Three to four days appeared to be required for maximum response. The effect was also observed in animals maintained on a protein rich diet, in which the basic hepatic malic enzyme activity was low, but not in animals maintained on a sucrose rich diet, in which the basic enzyme activity was almost twice normal. Methyl cholanthrene, administered by daily intraperitoneal injection (40 mg/kg body weight), resulted in elevated hepatic levels not only of malic enzyme but also of the pentose phosphate pathway dehydrogenases. The timing of the "starve-refeed" response of the hepatic NADP-linked dehydrogenases in phenobarbitone-treated rats was similar to that in controls, and similar maximum enzyme activities were reached. The role of cytoplasmic NADP-linked dehydrogenases in the provision of reducing equivalent is discussed, particularly in relation to hepatic microsomal drug metabolism.
D000818:Animals; D003593:Cytoplasm / Q000201:enzymology; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D005215:Fasting; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008291:Malate Dehydrogenase / Q000378:metabolism; D008748:Methylcholanthrene / Q000494:pharmacology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010428:Pentosephosphates; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats; D013395:Sucrose / Q000494:pharmacology
D004040:Dietary Carbohydrates; D010428:Pentosephosphates; D008748:Methylcholanthrene; D013395:Sucrose; D008291:Malate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D009247:NADH, NADPH Oxidoreductases; D010634:Phenobarbital