Compartmentation of lactate and glucose metabolism in C6 glioma cells -: A 13C and 1H NMR study
Compartmentation of lactate and glucose metabolism in C6 glioma cells -: A 13C and 1H NMR study
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DOI：
10.1074/jbc.273.42.27162
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发表时间：
1998-10-16
影响因子：
4.8
通讯作者：
Merle, M
中科院分区：
文献类型：
--
作者：
Bouzier, AK;Goodwin, R;Merle, M
用~（13）C和~（11）H核磁共振谱研究了C_6胶质瘤细胞中L-乳酸和D-葡萄糖的代谢。用5.5mM葡萄糖和11 mM乳酸孵育C_6胶质瘤细胞，细胞外液中乳酸和葡萄糖浓度的变化表明，乳酸的净产生是一种活跃的有氧糖酵解的结果。在含有两种底物的培养基中孵育4小时后，测定各种代谢物的C-13富集，每种底物以[3-C-13] L-乳酸盐或[1-C-13] D-葡萄糖的形式交替标记。使用11 mM [3-C-13] L-乳酸盐，发现谷氨酸C4的富集为69%，高于丙氨酸C3的富集为32%，而乙酰辅酶A C2的富集为78%。这些结果表明，外源性乳酸是细胞氧化代谢的主要底物，但糖酵解活跃，导致净乳酸产生。然而，这种乳酸盐在代谢上不同于外源性乳酸盐，因为两种乳酸盐物质没有混合到一个独特的隔室中。结果实际上与存在乳酸盐和丙酮酸盐两个库的概念一致，其中一个库与外源性乳酸盐密切相关，是氧化代谢的主要燃料，另一个库与有氧糖酵解密切相关。
C-13 and H-1 NMR spectroscopy was used to investigate the metabolism of L-lactate and D-glucose in C6 glioma cells, The changing of lactate and glucose concentration in the extracellular medium of C6 glioma cells incubated with 5.5 mM glucose and 11 mM lactate indicated a net production of lactate as the consequence of an active aerobic glycolysis. The C-13 enrichments of various metabolites were determined after 4-h cell incubation in media containing both substrates, each of them being alternatively labeled in the form of either [3-C-13]L-lactate or [1-C-13]D-glucose. Using 11 mM [3-C-13]L-lactate, the enrichment of glutamate C4, 69%, was found higher than that of alanine C3, 32%, when that of acetyl-CoA C2 was 78%. These results indicated that exogenous lactate was the major substrate for the oxidative metabolism of the cells, Nevertheless, an active glycolysis occurred, leading to a net lactate production. This lactate was, however, metabolically different from the exogenous lactate as both lactate species did not mix into a unique compartment, The results were actually consistent with the concept of the existence of two pools of both lactate and pyruvate, wherein one pool was closely connected with exogenous lactate and was the main fuel for the oxidative metabolism, and the other pool was closely related to aerobic glycolysis.