Noninvasive measurements of [1-13C]glycogen concentrations and metabolism in rat brain in vivo
Noninvasive measurements of [1-13C]glycogen concentrations and metabolism in rat brain in vivo
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DOI：
10.1046/j.1471-4159.1999.0731300.x
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发表时间：
1999-09-01
影响因子：
4.7
通讯作者：
Gruetter, R
中科院分区：
文献类型：
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作者：
Choi, IY;Tkác, I;Gruetter, R
使用特定的C-13 NMR定位方法，在完整大鼠中注入[1-C-13]葡萄糖时测量C-13标记掺入糖原C1共振。[1-C-13]糖原的最大浓度为5.1 +/- 0.6 μ mol g（-1）（平均值+/- SE，n = 8）。在急性高血糖的最初60分钟内，（合成酶通量）为2.3 +/- 0.7 μ mol g（-1）h（-1）（平均值+/- SE，n = 9只大鼠），高于（p < 0.01）大于或等于2小时后测量的0.49 +/- 0.14 μ mol g（-1）h（-1）速率。为了评估C-13标记的掺入是否是由于周转或净合成，在7只大鼠中继续输注未标记的葡萄糖。C-13标记下降速率（磷酸化酶通量）低于标记掺入的初始速率（0.33 +/- 0.10 μ mol g（-1）h（-1））（p < 0.01），并且似乎与前一次输注[1-C-13]葡萄糖的持续时间无关（相关性p > 0.05）。结果表明，与以前的报道相似，已经发生了类似于3 μ mol g（-1）的净糖原合成。在三项研究中，当在[1-C-13]葡萄糖之前输注未标记葡萄糖时，糖原C1积累的速率为0.46 +/- 0.08 μ mol g（-1）h（-1）。结果表明，高血糖期间稳态糖原周转率与葡萄糖消耗量的1%相似。
Using a specific C-13 NMR localization method, C-13 label incorporation into the glycogen C1 resonance was measured while infusing [1-C-13]glucose in intact rats. The maximal concentration of [1-C-13]glycogen was 5.1 +/- 0.6 mu mol g(-1) (mean +/- SE, n = 8). During the first 60 min of acute hyperglycemia, the rate of C-13 label incorporation (synthase flux) was 2.3 +/- 0.7 mu mol g(-1) h(-1) (mean +/- SE, n = 9 rats), which was higher (p < 0.01) than the rate of 0.49 +/- 0.14 mu mol g(-1) h(-1) measured greater than or equal to 2 h later. To assess whether the incorporation of C-13 label was due to turnover or net synthesis, the infusion was continued in seven rats with unlabeled glucose. The rate of C-13 label decline (phosphorylase flux) was lower (0.33 +/- 0.10 mu mol g(-1) h(-1)) than the initial rate of label incorporation (p < 0.01) and appeared to be independent of the duration of the preceding infusion of [1-C-13]glucose (p > 0.05 for correlation). The results implied that net glycogen synthesis of similar to 3 mu mol g(-1) had occurred, similar to previous reports. When infusing unlabeled glucose before [1-C-13]glucose in three studies, the rate of glycogen C1 accumulation was 0.46 +/- 0.08 mu mol g(-1) h(-1). The results suggest that steady-state glycogen turnover rates during hyperglycemia are similar to 1% of glucose consumption.