EFFECTS OF ETHANOL ON ALANINE METABOLISM IN PERFUSED MOUSE-LIVER STUDIED BY C-13 NMR
EFFECTS OF ETHANOL ON ALANINE METABOLISM IN PERFUSED MOUSE-LIVER STUDIED BY C-13 NMR
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DOI：
10.1073/pnas.76.10.4808
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
MCLAUGHLIN, AC
中科院分区：
文献类型：
--
作者：
COHEN, SM;SHULMAN, RG;MCLAUGHLIN, AC
Time courses of 13C labeling from alanine and ethanol in perfused mouse livers were followed by NMR. The enrichment at specific carbons of glucose, glutamate, glutamine, aspartate, acetate, acetoacetate, .beta.-hydroxybutyrate and lactate was measured. The specific labeling of glutamate in the presence of labelel 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-Cl 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 h earlier), providing a method for studying flow through glutamine synthetase in situ.
