Dephosphorylation of 2-deoxyglucose 6-phosphate and 2-deoxyglucose export from cultured astrocytes

被引:12
作者
Forsyth, RJ [1 ]
Bartlett, K [1 ]
Eyre, J [1 ]
机构
[1] ROYAL VICTORIA INFIRM,SIR JAMES SPENCE INST CHILD HLTH,DEPT CHILD HLTH,NEWCASTLE TYNE NE1 4LP,TYNE & WEAR,ENGLAND
基金
英国惠康基金;
关键词
D O I
10.1016/0197-0186(95)00095-X
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Neurotransmitter-stimulated mobilization of astrocyte glycogen has been proposed as a basis for local energy homeostasis in brain. However, uncertainty remains over the fate of astrocyte glycogen. Upon transfer of cultured astrocytes pre-loaded with [2-H-3]2-deoxyglucose 6-phosphate at non-tracer concentrations to a glucose-free, 2-deoxyglucose-free medium. rapid dephosphorylation of a proportion of the intracellular 2-deoxyglucose 6-phosphate pool and export of 2-deoxyglucose to the extracellular fluid occurs. Astrocytes show very low, basal rates of gluconeogenesis from pyruvate (approx. 1 nmol mg protein(-1) h(-1)). Astrocytes in vivo may be capable of physiologically significant glucose export from glucose 6-phosphate. The low gluconeogenic activity in astrocytes suggests that the most likely source of glucose-6-phosphate may be glycogen. These findings support the hypothesis that export, as glucose, to adjacent neurons may be one of the possible fate(s) of astrocytic glycogen. Such export of glycogen as glucose occurring in response to increases in neuronal activity could contribute to energy homeostasis on a paracrine scale within brain.
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页码:243 / 250
页数:8
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