Lactate formation from [U- 13C]aspartate in cultured astrocytes: compartmentation of pyruvate metabolism

• Published in: Neuroscience letters Vol. 237; no. 2; pp. 117 - 120
• Main Authors: Bakken, Inger Johanne, White, Linda R, Aasly, Jan, Unsgård, Geirmund, Sonnewald, Ursula
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 21.11.1997; Elsevier
• Subjects: 13C Nuclear magnetic resonance spectroscopy; Animals; Aspartate; Aspartic Acid - metabolism; Astrocytes; Astrocytes - enzymology; Astrocytes - metabolism; Biological and medical sciences; Cells, Cultured; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; Isolated neuron and nerve. Neuroglia; Lactic Acid - biosynthesis; Magnetic Resonance Spectroscopy; Malic enzyme; Mice; Phosphoenolpyruvate carboxykinase; Phosphoenolpyruvate Carboxykinase (ATP) - antagonists & inhibitors; Phosphoenolpyruvate Carboxykinase (ATP) - metabolism; Pyruvic Acid - metabolism; Vertebrates: nervous system and sense organs; Aspartate; Astrocytes; Phosphoenolpyruvate carboxykinase; Malic enzyme; 13C Nuclear magnetic resonance spectroscopy; Cerebral cortex; Neuroglia; Rodentia; Central nervous system; Pyruvate; Astrocyte; Metabolism; In vitro; Lactates; Vertebrata; Mammalia; Mouse; Excitatory aminoacid; Neurotransmitter; Brain (vertebrata)
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(97)00834-3

Metabolism of [U- 13C]aspartate in cultured astrocytes and the effects of inhibitors of malic enzyme and phosphoenolpyruvate carboxykinase (hydroxymalonate and 3-mercaptopicolinic acid, respectively) were studied using 13C nuclear magnetic resonance (NMR) spectroscopy. The labelling of glutamate and glutamine showed entry of aspartate into the tricarboxylic acid (TCA) cycle after conversion to oxaloacetate. Production of [U- 13C]pyruvate from [U- 13C]aspartate was revealed by the presence of [U- 13C]lactate in incubation media. Furthermore, labelling patterns in C-2 and C-3 in intracellular aspartate showed entry of [1,2– 13C]acetyl-CoA into the TCA cycle; evidence for pyruvate-recycling. No reduction in [U- 13C]lactate was observed in the presence of either enzyme inhibitor. However, 3-mercaptopicolinic acid reduced incorporation of labelled acetyl-CoA into TCA cycle intermediates, indicating compartmentation of pyruvate production in astrocytes.