Effects of ethanol on alanine metabolism in perfused mouse liver studied by 13C NMR.
AUTOR(ES)
Cohen, S M
RESUMO
Time courses of 13C labeling from alanine and ethanol in perfused mouse livers have been followed by NMR. The enrichment at specific carbons of glucose, glutamate, glutamine, aspartate, acetate, acetoacetate, beta-hydroxybutyrate, and lactate has been measured. The specific labeling of glutamate in the presence of labeled alanine and labeled or unlabeled ethanol shows that, under these conditions, alanine enters the tricarboxylic acid cycle almost exclusively through pyruvate carboxylation, whereas ethanol is the exclusive source of acetyl-CoA. In the absence of ethanol, the alanine label flows through both paths. By comparing the scrambling of 13C between C3 and C2 of glutamate it is possible to estimate the mitochondrial fumarase activity; the C6-to-C5 ratios in glucose give the additional scrambling by cytosolic fumarase activity. In addition, the C6-to-C1 and C5-to-C2 ratios in glucose show that there is about 15% flux through the pentose cycle. Finally, the C4-to-C2 ratios in glutamine and glutamate are unequal at any time (the glutamine labels reflect the label distribution in glutamate measured 1 hr earlier), providing a method for studying flow through glutamine synthetase in situ.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=413026Documentos Relacionados
- Rapid ATP assays in perfused mouse liver by 31P NMR.
- Detection of human muscle glycogen by natural abundance 13C NMR.
- Direct observation of glycogen synthesis in human muscle with 13C NMR.
- 13C NMR study of the effects of leptin treatment on kinetics of hepatic intermediary metabolism
- Pyruvate metabolism in Halobacterium salinarium studied by intracellular 13C nuclear magnetic resonance spectroscopy.