title: Malic enzyme levels are increased by the activation of NADPH-consuming pathways: detoxification processes.
abstract: The administration to rats of either t-butyl hydroperoxide or phenobarbital, compounds that are metabolized through detoxification processes, produces an increase in specific activity of the NADPH-consuming enzymes, glutathione reductase and NADPH-cytochrome c reductase. These compounds also produce a very significant increase in the specific activity of malic enzyme. Immunoprecipitation with a specific antibody for malic enzyme indicates that specific activity changes are the result of corresponding changes in the amounts of enzyme protein present. The administration of 1,3-bis(chloroethyl(-1-nitrosourea (a glutathione reductase inhibitor) together with t-butyl hydroperoxide abolishes any stimulation of malic enzyme activity. These results indicate that an increase in NADPH consumption induces the synthesis of malic enzyme. Alternatively, a protection of enzyme degradation cannot be rigorously excluded.
mesh_terms: D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D002330:Carmustine / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005980:Glutathione Reductase / Q000378:metabolism; D007120:Immunochemistry; D008658:Inactivation, Metabolic; D008291:Malate Dehydrogenase / Q000096:biosynthesis*; D009249:NADP / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010545:Peroxides / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D020122:tert-Butylhydroperoxide
chemical_list: D010545:Peroxides; D009249:NADP; D020122:tert-Butylhydroperoxide; D008291:Malate Dehydrogenase; D009251:NADPH-Ferrihemoprotein Reductase; D005980:Glutathione Reductase; D002330:Carmustine; D010634:Phenobarbital