title: Rat brain slices oxidize glucose at high rates: a (13)C NMR study.
abstract: Since glucose is the main cerebral substrate, we have characterized the metabolism of various (13)C glucose isotopomers in rat brain slices. For this, we have used our cellular metabolomic approach that combines enzymatic and carbon 13 NMR techniques with mathematical models of metabolic pathways. We identified the fate and the pathways of the conversion of glucose carbons into various products (pyruvate, lactate, alanine, aspartate, glutamate, GABA, glutamine and CO(2)) and determined absolute fluxes through pathways of glucose metabolism. After 60 min of incubation, lactate and CO(2) were the main end-products of the metabolism of glucose which was avidly metabolized by the slices. Lactate was also used at high rates by the slices and mainly converted into CO(2). High values of flux through pyruvate carboxylase, which were similar with glucose and lactate as substrate, were observed. The addition of glutamine, but not of acetate, stimulated pyruvate carboxylation, the conversion of glutamate into succinate and fluxes through succinate dehydrogenase, malic enzyme, glutamine synthetase and aspartate aminotransferase. It is concluded that, unlike brain cells in culture, and consistent with high fluxes through PDH and enzymes of the tricarboxylic acid cycle, rat brain slices oxidized both glucose and lactate at high rates.
authors: Institut National de la Santé et de la Recherche Médicale, Unit # 820 (Métabolomique et Maladies Métaboliques), 69372 Lyon Cedex 08, France. maha-elhage@hotmail.com
authors: Maha
authors: M
authors: El Hage
authors: Bernard
authors: B
authors: Ferrier
authors: Gabriel
authors: G
authors: Baverel
authors: Guy
authors: G
authors: Martin
mesh_terms: D000085:Acetates / Q000378:metabolism; D000758:Anesthesia / Q000379:methods; D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002247:Carbon Isotopes; D005947:Glucose / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D000085:Acetates; D000777:Anesthetics; D002247:Carbon Isotopes; D005971:Glutamates; D005973:Glutamine; D001224:Aspartic Acid; D019344:Lactic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D019289:Pyruvic Acid; D005974:Glutamate-Ammonia Ligase; D005947:Glucose