title: Nitrous oxide exposure reduces hepatic C1-tetrahydrofolate synthase expression in rats.
abstract: C1-tetrahydrofolate synthase (C1-THF synthase) is a trifunctional enzyme which catalyzes the interconversion of one-carbon units attached to the coenzyme THF. Nitrous oxide (N2O) inhalation is known to inactivate hepatic cobalamin-dependent methionine synthase leading to methionine deficiency and trapping of THF in the methyl-THF form. Liver tissue from rats exposed to N2O for 48 hours exhibited a coordinate decrease in all three activities of C1-THF synthase of approximately 25%. A corresponding 25% decrease in immunoreactive C1-THF synthase was also observed after 48 hours. Thus, the decrease in the concentration of C1-THF synthase accounted entirely for the decreases observed in the three activities. These results suggest that perturbations of hepatic THF pools by N2O affect the level of C1-THF synthase expression at a translational or pretranslational level.
authors.affiliation: Clayton Foundation Biochemical Institute, Department of Chemistry, University of Texas 78712.
authors.forename: C K
authors.initials: CK
authors.lastname: Barlowe
authors.forename: D R
authors.initials: DR
authors.lastname: Appling
mesh_terms: D000619:Aminohydrolases / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D005574:Formate-Tetrahydrofolate Ligase / Q000276:immunology / Q000378:metabolism*; D008025:Ligases / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP) / Q000276:immunology / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000276:immunology / Q000378:metabolism*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
chemical_list: D009097:Multienzyme Complexes; C021836:formyl-methenyl-methylenetetrahydrofolate synthetase; D010088:Oxidoreductases; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP); D000619:Aminohydrolases; D008025:Ligases; D005574:Formate-Tetrahydrofolate Ligase; D009609:Nitrous Oxide