Measurement of plasma protein synthesis rate in infant pig: an investigation of alternative tracer approaches.
Measurement of plasma protein synthesis rate in infant pig: an investigation of alternative tracer approaches.
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幼猪血浆蛋白合成率的测量：替代示踪剂方法的研究。
DOI：
10.1152/ajpregu.1994.267.1.r221
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Frazer,M
中科院分区：
文献类型：
--
作者：
Jahoor,F;Burrin,DG;Reeds,PJ;Frazer,M
为了设计一种测量血浆蛋白合成的新方法，我们验证了一个假设，即当[U-13C]葡萄糖用于合成[U-13C]丙氨酸时，血浆丙酮酸和丙氨酸将与用于合成血浆蛋白的丙氨酸处于同位素平衡状态。通过输注[U-13C]葡萄糖、[2H3]亮氨酸和[2H4]赖氨酸，测定7头仔猪中标记亮氨酸、赖氨酸和丙氨酸与极低密度脂蛋白（VLDL）载脂蛋白B (apoB)-100、白蛋白和纤维蛋白原的掺入情况。血浆丙氨酸（2.29 +/- 0.29）、丙酮酸（2.5 +/- 0.33）和载脂蛋白-丙氨酸（2.33 +/- 0.25）的平台浓度无显著差异。利用载脂蛋白结合赖氨酸、亮氨酸和丙氨酸作为前体的同位素富集计算的纤维蛋白原和白蛋白的分数合成率与基于血浆丙氨酸的合成率相似。这些结果表明肝内前体丙氨酸池和血浆丙氨酸处于同位素平衡状态。因此，血浆蛋白合成可以通过输注[U-13C]葡萄糖和血浆丙氨酸作为前体来测量。
To devise a new method to measure plasma protein synthesis, we tested the hypothesis that, when [U-13C]glucose is used to produce [U-13C]alanine, plasma pyruvate and alanine will be in isotopic equilibrium with the alanine used to synthesize plasma proteins. The incorporation of labeled leucine, lysine, and alanine into very-low-density lipoprotein (VLDL) apolipoprotein B (apoB)-100, albumin, and fibrinogen was measured in seven infant pigs by infusing [U-13C]glucose, [2H3]leucine, and [2H4]lysine. The plateau enrichments of plasma alanine (2.29 +/- 0.29), pyruvate (2.5 +/- 0.33), and apoB-alanine (2.33 +/- 0.25) were not different. The fractional synthesis rates of fibrinogen and albumin calculated using the isotopic enrichments of apoB-bound lysine, leucine, and alanine as the precursor were similar to those based on plasma alanine. These results suggest that the intrahepatic precursor alanine pool and plasma alanine were in isotopic equilibrium. Thus plasma protein synthesis can be measured by infusing [U-13C]glucose and using plasma alanine as precursor.