ACID LABILITY OF METABOLITES OF 2-DEOXYGLUCOSE IN RAT-BRAIN - IMPLICATIONS FOR ESTIMATES OF KINETIC-PARAMETERS OF DEOXYGLUCOSE PHOSPHORYLATION AND TRANSPORT BETWEEN BLOOD AND BRAIN
ACID LABILITY OF METABOLITES OF 2-DEOXYGLUCOSE IN RAT-BRAIN - IMPLICATIONS FOR ESTIMATES OF KINETIC-PARAMETERS OF DEOXYGLUCOSE PHOSPHORYLATION AND TRANSPORT BETWEEN BLOOD AND BRAIN
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DOI：
10.1111/j.1471-4159.1990.tb01981.x
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发表时间：
1990-04-01
影响因子：
4.7
通讯作者：
SOKOLOFF, L
中科院分区：
文献类型：
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作者：
DIENEL, GA;CRUZ, NF;SOKOLOFF, L
低血糖大鼠脑内[14C]脱氧葡萄糖([14C]DG)的稳态脑/血浆分配比([14C]DG)先前通过测量冷冻吹风脑和血浆中的DG浓度，超过了DG模型动力学模拟所预测的结果。高估了转运和磷酸化的[14C]DG前体池的真实大小，这可能是因为在实验期间或提取过程中，[14C]DG在脑内的隔离和/或[14C]DG代谢的不稳定和游离[14C]DG的再生。在本研究中，比较了用高氯酸或含65%乙醇的磷酸盐缓冲盐水平行提取的大鼠脑和血浆中[14C]DG和葡萄糖的浓度。脑酸提取液中两种己糖含量均高于乙醇提取液，而血浆中己糖含量不受提取步骤的影响。DG含量的高估程度(约1.2-4倍)随葡萄糖水平而变化，并在低血糖大鼠的提取物中最高；[14C]DG部分被14C标记的非酸性代谢物污染也是导致这种高估的原因之一。脑酸提取物中的葡萄糖浓度比乙醇提取物中的葡萄糖浓度高出
The steady-state brain/plasma distribution ratios of [14C]deoxyglucose ([14C]DG) for hypoglycemic rats previously determined by measurement of DG concentrations in neutralized acid extracts of freeze-blown brain and plasma exceeded those predicted by simulations of kinetics of the DG model. Overestimation of the true size of the precursor pool of [14C]DG for transport and phosphorylation could arise from sequestration of [14C]DG within brain compartments and/or instability of metabolities of [14C]DG and regeneration of free [14C]DG during the experimental period or extraction procedure. In the present study, the concentrations of [14C]DG and glucose were compared in samples of rat brain and plasma extracted in parallel with perchloric acid or 65% ethanol containing phosphate-buffered saline. The concentrations of both hexoses in acid extracts of brain were higher than those in ethanol, whereas hexose contents of plasma were not dependent on the extraction procedure. The magnitude of overestimation of DG content (about 1.2-to fourfold) varied with glucose level and was highest in extracts isolated from hypoglycemic rats; contamination of the [14C]DG fraction with 14C-labeled nonacidic metabolites also contributed to this overestimation. Glucose concentrations in acid extracts of brain exceeded those of the ethanol extracts by