Arginine and Ornithine Are the Main Precursors for Citrulline Synthesis in Mice
Arginine and Ornithine Are the Main Precursors for Citrulline Synthesis in Mice
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DOI：
10.3945/jn.111.153825
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发表时间：
2012-03-01
影响因子：
4.2
通讯作者：
Marini, Juan C.
中科院分区：
文献类型：
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作者：
Marini, Juan C.
最近在小鼠、仔猪和人类中进行的同位素示踪剂研究在瓜氨酸和精氨酸合成的主要碳骨架前体方面产生了相互矛盾的结果。这可能部分是由于注入不同的示踪剂和用于解释稳定同位素数据的模型。此外，以往的研究通常针对单一的前体，这就阻碍了多个前体之间的直接比较。为了进一步阐明不同前体对瓜氨酸合成的贡献，在吸收后和餐后阶段，使用多示踪剂方案在小鼠模型中研究了瓜氨酸的所有可能的肠内和血浆前体。此外，三种不同的模型被用来解释稳定同位素数据。经典的示踪剂乘积方程的利用，为静脉输注示踪剂开发，但也用于包括静脉输注示踪剂。示踪剂，严重高估了肠道前体的贡献。无论采用哪种模型，饮食和血浆精氨酸是进食期间瓜氨酸合成的主要前体，也是禁食期间血浆精氨酸合成的主要前体。精氨酸的作用直接在瓜氨酸合成位点，并通过血浆鸟氨酸。在本研究中观察到的精氨酸和鸟氨酸的主要作用支持了在小鼠、仔猪和人类中的观察结果，表明鸟氨酸氨基转移酶是该途径中的关键酶。J.营养142：572-580，2012.
Recent isotopic tracer studies in mice, piglets, and humans have produced conflicting results as to the main carbon skeleton precursor for citrulline and arginine synthesis. This may be due in part to the different tracers infused and models used to interpret the stable isotope data. Furthermore, previous studies usually investigated a single precursor, which prevented the direct comparison among multiple precursors. To further elucidate the contribution of different precursors to citrulline synthesis, all possible enteral and plasma precursors of citrulline were studied in a mouse model during the postabsorptive and postprandial period using multitracer protocols. In addition, three different models were used to interpret the stable isotope data. The utilization of the classic precursor-product equation, developed for i.v. infused tracers but also used to include i.g. tracers, grossly overestimated the contribution of enteral precursors. Regardless of the model employed, dietary and plasma arginine were the main precursors for citrulline synthesis during feeding and plasma arginine during feed deprivation. The contribution of arginine was directly at the site of citrulline synthesis and through plasma ornithine. The predominant role of arginine and ornithine seen in this study supports the observations in mice, piglets, and humans suggesting that ornithine amino transferase is a pivotal enzyme in this pathway. J. Nutr. 142: 572-580, 2012.