Glutamine is an important precursor for de novo synthesis of arginine in humans
Glutamine is an important precursor for de novo synthesis of arginine in humans
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DOI：
10.1093/ajcn/87.5.1282
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发表时间：
2008-05-01
影响因子：
7.1
通讯作者：
van Leeuwen, Paul A. M.
中科院分区：
文献类型：
--
作者：
Ligthart-Melis, Gerdien C.;van de Poll, Marcel C. G.;van Leeuwen, Paul A. M.
背景资料：谷氨酰胺和精氨酸之间存在代谢关系，这两种氨基酸具有促进重病患者恢复的特性。这是可能的，谷氨酰胺发挥其有益作用的一部分，通过提高可用性的arginine.Objectives：我们的目的是量化后吸收条件下的血浆谷氨酰胺通过中间体瓜氨酸精氨酸的代谢途径，并建立肾脏的贡献，以合成arginine.Design：这项研究是在手术过程中进行的患者。通过静脉注射氨基酸的稳定同位素示踪剂，研究了谷氨酰胺、瓜氨酸和精氨酸的代谢。结果用建立的方程进行解释。参数检验用于检验和关联结果。结果：谷氨酰胺、瓜氨酸和精氨酸的平均（SE）全身血浆周转率分别为240 +/-14、6.2 +/-0.6和42 +/-2.9 μ mol。kg（-1）。h（-1），差异有显著性（P <0.01）。来自谷氨酰胺的瓜氨酸的血浆周转率为5.1 +/-0.7 μ mol。kg（-1）。h（-1），瓜氨酸衍生的精氨酸为4.9 +/-0.9 μ mol。kg（-1）。h（-1）（P <0.01）。经计算，血浆谷氨酰胺对源自血浆瓜氨酸的血浆精氨酸的贡献为64%。观察到肾脏吸收了> 50%的循环血浆瓜氨酸，并将等摩尔量的精氨酸释放到血浆中。结论：本研究表明，谷氨酰胺是人体精氨酸合成的重要前体。这也为未来探索谷氨酰胺治疗剂量和给药途径（肠内或胃肠外）的影响的研究提供了坚实的基础。
Background: A metabolic relation exists between glutamine and arginine, 2 amino acids with properties that enhance the recovery of seriously ill patients. It is possible that glutamine exerts part of its beneficial effects by enhancing the availability of arginine.Objectives: We aimed to quantify under postabsorptive conditions the metabolic pathway of plasma glutamine into arginine via the intermediate citrulline and to establish the contribution of the kidneys to the synthesis of arginine.Design: The study was conducted in patients during surgery. The metabolism of glutamine, citrulline, and arginine was studied by using intravenous administration of stable isotope tracers of the amino acids. Results were interpreted by using established equations. Parametric tests were used to test and correlate results. P < 0.05 was regarded as significant.Results: Mean (SE) whole-body plasma turnover rates of glutamine, citrulline, and arginine were 240 +/- 14, 6.2 +/- 0.6, and 42 +/- 2.9 mu mol . kg(-1) . h(-1), respectively (P < 0.01). Plasma turnover of citrulline derived from glutamine was shown to be 5.1 +/- 0.7 mu mol . kg(-1) . h(-1), and arginine derived from citrulline was shown to be 4.9 +/- 0.9 mu mol . kg(-1) . h(-1) (P < 0.01). The contribution of plasma glutamine to plasma arginine derived from plasma citrulline was calculated to be 64%. The kidneys were observed to take up >50% of circulating plasma citrulline and to release equimolar amounts of arginine into plasma.Conclusions: This study shows that glutamine is an important precursor for the synthesis of arginine in humans. It also provides a firm basis for future studies exploring the effect of a treatment dose and the route of administration (enteral or parenteral) of glutamine.