Institute of Functional Biology and Genomics (IBFG), University of Salamanca-CSIC, Salamanca, Spain.
J Cereb Blood Flow Metab. 2013 Dec;33(12):1843-5. doi: 10.1038/jcbfm.2013.168. Epub 2013 Sep 25.
The rates of glucose oxidized at glycolysis and pentose-phosphate pathway (PPP) in neurons are controversial. Using [3-(3)H]-, [1-(14)C]-, and [6-(14)C]glucose to estimate fluxes through these pathways in resting, intact rat cortical primary neurons, we found that the rate of glucose oxidized through PPP was, apparently, ∼14% of total glucose metabolized. However, inhibition of PPP rate-limiting step, glucose-6-phosphate (G6P) dehydrogenase, increased approximately twofold the glycolytic rate; and, knockdown of phosphoglucose isomerase increased ∼1.8-fold the PPP rate. Thus, in neurons, a considerable fraction of fructose-6-phosphate returning from the PPP contributes to the G6P pool that re-enters PPP, largely underestimating its flux.
神经元糖酵解和磷酸戊糖途径（PPP）中葡萄糖氧化的速率存在争议。使用[3-(3)H] - 、[1-(14)C] - 和[6-(14)C] - 葡萄糖来估计在休息、完整的大鼠皮质原代神经元中这些途径的通量，我们发现 PPP 途径中葡萄糖氧化的速率显然约为总葡萄糖代谢的 14%。然而，抑制 PPP 限速步骤葡萄糖-6-磷酸（G6P）脱氢酶使糖酵解速率增加约两倍；磷酸葡萄糖异构酶的敲低使 PPP 速率增加了约 1.8 倍。因此，在神经元中，从 PPP 返回的相当一部分果糖-6-磷酸有助于重新进入 PPP 的 G6P 池，这大大低估了其通量。
