The metabolism of [3-13C]lactate in the rat brain is specific of a pyruvate carboxylase-deprived compartment
The metabolism of [3-13C]lactate in the rat brain is specific of a pyruvate carboxylase-deprived compartment
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DOI：
10.1046/j.1471-4159.2000.0750480.x
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发表时间：
2000-08-01
影响因子：
4.7
通讯作者：
Merle, M
中科院分区：
文献类型：
--
作者：
Bouzier, AK;Thiaudiere, E;Merle, M
乳酸代谢在成年大鼠脑中的关系进行了研究与星形胶质细胞和神经元之间的乳酸运输的概念。Wistar大鼠静脉输注含有[3-C-13]乳酸盐（534 mM）或葡萄糖（750 mM）和[3-C-13]乳酸盐（534 mM）的溶液。测定血糖和乳酸的浓度和C-13富集的时间过程。数据表明，[3-C-13]乳酸通过肝脏再生再循环。然而，当使用含葡萄糖的输注液时，葡萄糖标记的产率降低。输注20分钟或1小时后，制备脑组织的高氯酸提取物，随后通过C-13和H-1观察/C-13编辑NMR光谱进行分析。氨基酸的C-13标记表明[3-C-13]乳酸在脑中代谢。基于丙氨酸C3富集，在所使用的最有利条件下，乳酸对脑代谢的贡献达35%。与[1-C-13]葡萄糖代谢相比，证明谷氨酰胺C2和C3标记无差异，表明乳酸在缺乏丙酮酸羧化酶活性的隔室中代谢。这一结果首次从体内研究中证实，乳酸盐更具体地是神经元底物。
Lactate metabolism in the adult rat brain was investigated in relation with the concept of lactate trafficking between astrocytes and neurons. Wistar rats were infused intravenously with a solution containing either [3-C-13]lactate (534 mM) or both glucose (750 mM) and [3-C-13]lactate (534 mM). The time courses of both the concentration and C-13 enrichment of blood glucose and lactate were determined. The data indicated the occurrence of [3-C-13]actate recycling through liver gluconeogenesis. The yield of glucose labeling was, however, reduced when using the glucose-containing infusate. After a 20-min or 1-h infusion, perchloric acid extracts of the brain tissue were prepared and subsequently analyzed by C-13- and H-1-observed/C-13-edited NMR spectroscopy. The C-13 labeling of amino acids indicated that [3-C-13]lactate was metabolized in the brain. Based on the alanine C3 enrichment, lactate contribution to brain metabolism amounted to 35% under the most favorable conditions used. By contrast with what happens with [1-C-13]glucose metabolism, no difference in glutamine C2 and C3 labeling was evidenced, indicating that lactate was metabolized in a compartment deprived of pyruvate carboxylase activity. This result confirms, for the first time from an in vivo study, that lactate is more specifically a neuronal substrate.