Estimation of glucose carbon recycling and glucose turnover with [U-13C] glucose.
Estimation of glucose carbon recycling and glucose turnover with [U-13C] glucose.
复制标题
使用 [U-13C] 葡萄糖估算葡萄糖碳循环和葡萄糖周转率。
DOI：
10.1152/ajpendo.1983.245.5.e476
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Kalhan,SC
中科院分区：
文献类型：
--
作者：
Tserng,KY;Kalhan,SC
为了估计人类葡萄糖生产的“真实”速率以及葡萄糖碳循环，开发了一种以[U-13C]葡萄糖作为示踪剂的质谱方法。由于统一标记的葡萄糖（[13C6]葡萄糖）以[13C6]葡萄糖的形式回收的机会可以忽略不计，因此通过使用化学电离质谱法测量[13C6]葡萄糖的血浆同位素富集来获得真实的葡萄糖生产率。相反，当通过酶脱羧和比率质谱法测量葡萄糖C-1的同位素富集时，获得了包括碳回收的“表观”葡萄糖产量。两个速率之间的差异是葡萄糖碳回收的程度。将[U-13C]葡萄糖作为引发的恒速输注给予六名正常健康成年受试者。应用稳态动力学从示踪剂稀释中计算葡萄糖周转率。本方法估计的真实葡萄糖生成率为 2.02 +/- 0.19 mg X kg-1 X min-1（平均值 +/- SD）。经过一整夜的禁食后，葡萄糖碳循环贡献了总葡萄糖生产率的 3% 至 26%。使用稳定同位素和质谱技术可以估计葡萄糖代谢的重要参数，而无需求助于多种示踪剂，同时防止辐射风险。
To estimate "true" rate of glucose production, as well as glucose carbon recycling in humans, a mass spectrometric method with [U-13C]glucose as tracer was developed. Because the opportunity for the uniformly labeled glucose, [13C6]glucose, to recycle back as [13C6]glucose is negligible, the true glucose production rate was obtained by measuring the plasma isotope enrichment of [13C6]glucose with chemical ionization mass spectrometry. In contrast, when the isotopic enrichment of C-1 of glucose was measured by enzymatic decarboxylation and ratio mass spectrometry, the "apparent" glucose production including carbon recycling was obtained. The difference between the two rates was the extent of glucose carbon recycling. [U-13C]glucose was administered as primed constant-rate infusion to six normal healthy adult subjects. Rates of glucose turnover were calculated from tracer dilution by applying steady-state kinetics. The true rate of glucose production estimated by the present method was 2.02 +/- 0.19 mg X kg-1 X min-1 (mean +/- SD). After an overnight fast, glucose carbon recycling contributed from 3 to 26% of the total glucose production rate. Use of stable isotopes and mass spectrometric technique permits estimation of important parameters of glucose metabolism without resorting to multiple tracers and at the same time preventing the risk of radiation.