Brain contains a functional glucose-6-phosphatase complex capable of endogenous glucose production
Brain contains a functional glucose-6-phosphatase complex capable of endogenous glucose production
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DOI：
10.1074/jbc.m410894200
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发表时间：
2005-03-25
影响因子：
4.8
通讯作者：
Chou, JY
中科院分区：
文献类型：
--
作者：
Ghosh, A;Cheung, YY;Chou, JY
葡萄糖对大脑的生存和功能是绝对必要的。在我们目前的理解中，大脑中没有内源性葡萄糖的产生，它完全依赖于血糖。这种葡萄糖是在两餐之间通过肝脏和肾脏中的葡萄糖-6-磷酸(GLC-6-P)的水解而产生的。最近，我们报道了一种普遍表达的GLC-6-P水解酶，即葡萄糖-6-磷酸酶-β(GLC-6-Pase-beta，GLC-6-Pase-beta)，它可以与GLC-6-P转运蛋白偶联，在糖原分解和糖异生的终末阶段将GLC-6-P水解为葡萄糖。星形胶质细胞是脑糖原的主要储存库，它同时表达GLC-6-Pase-β和GLC-6-P转运体活性，并且这些活性可以偶联形成活性的GLC-6-Pase复合体，提示星形胶质细胞可能是脑葡萄糖的内源性来源。
Glucose is absolutely essential for the survival and function of the brain. In our current understanding, there is no endogenous glucose production in the brain, and it is totally dependent upon blood glucose. This glucose is generated between meals by the hydrolysis of glucose-6-phosphate (Glc-6-P) in the liver and the kidney. Recently, we reported a ubiquitously expressed Glc-6-P hydrolase, glucose-6-phosphatase-beta (Glc-6-Pase-beta), that can couple with the Glc-6-P transporter to hydrolyze Glc-6-P to glucose in the terminal stages of glycogenolysis and gluconeogenesis. Here we show that astrocytes, the main reservoir of brain glycogen, express both the Glc-6-Pase-beta and Glc-6-P transporter activities and that these activities can couple to form an active Glc-6-Pase complex, suggesting that astrocytes may provide an endogenous source of brain glucose.