H-1 NMR studies of glucose transport in the human brain
H-1 NMR studies of glucose transport in the human brain
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DOI：
10.1097/00004647-199605000-00009
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发表时间：
1996-05-01
影响因子：
6.3
通讯作者：
Shulman, RG
中科院分区：
文献类型：
--
作者：
Gruetter, R;Novotny, EJ;Shulman, RG
在正常血糖期间和高血糖期间从人脑获得的H-1核磁共振（NMR）谱之间的差异被描绘为良好分辨的葡萄糖峰。在5项研究中，在4名年龄为18-22岁的健康受试者中测量了血浆葡萄糖快速增加期间这些脑葡萄糖变化的时间过程。结果表明，相对于血浆葡萄糖，葡萄糖的上升有显著滞后。积分对称Michaelis-Menten模型与相对葡萄糖信号的时间过程的拟合产生了4.8 +/- 2.4 mM的半最大转运的估计血浆葡萄糖浓度K-t（平均值+/- SD），最大转运速率Tmax为0.80 +/- 0.35 μ mol g（-1）min（-1），脑代谢葡萄糖消耗率（CMR）（glc）为0.32 +/- 0.16 μ mol g（-1）min（-1）。假设用C-13 NMR测定的脑葡萄糖浓度为1.0 μ mol/g，用相同的模型拟合脑葡萄糖浓度的时程，得到K-t = 3.9 +/- 0.82 mM，T-max = 1.16 +/- 0.29 μ mol g（-1）min（-1），和CMR（glc）= 0.35 +/- 0.10 μ mol g（-1）min（-1）。在这两种情况下，所得到的时间过程等于从通过C-13 NMR光谱法在实验分散内测定稳态葡萄糖浓度所预测的时间过程。确定运输动力学的两种方法之间的协议表明，葡萄糖分布在整个人脑的水相，这意味着大量的细胞内浓度。
The difference between H-1 nuclear magnetic resonance (NMR) spectra obtained from the human brain during euglycemia and during hyperglycemia is depicted as well-resolved glucose peaks, The time course of these brain glucose changes during a rapid increase in plasma glucose was measured in four healthy subjects, aged 18-22 years, in five studies. Results demonstrated a significant lag in the rise of glucose with respect to plasma glucose. The fit of the integrated symmetric Michaelis-Menten model to the time course of relative glucose signals yielded an estimated plasma glucose concentration for half maximal transport, K-t, of 4.8 +/- 2.4 mM (mean +/- SD), a maximal transport rate, T-max, of 0.80 +/- 0.35 mu mol g(-1) min(-1), and a cerebral metabolic glucose consumption rate (CMR)(glc) of 0.32 +/- 0.16 mu mol g(-1) min(-1). Assuming cerebral glucose concentration to be 1.0 mu mol/g at euglycemia as measured by C-13 NMR, the fit of the same model to the time course of brain glucose concentrations resulted in K-t = 3.9 +/- 0.82 mM, T-max = 1.16 +/- 0.29 mu mol g(-1) min(-1), and CMR(glc) = 0.35 +/- 0.10 mu mol g(-1) min(-1). In both cases, the resulting time course equaled that predicted from the determination of the steady-state glucose concentration by C-13 NMR spectroscopy within the experimental scatter. The agreement between the two methods of determining transport kinetics suggests that glucose is distributed throughout the entire aqueous phase of the human brain, implying substantial intracellular concentration.