RENAL AMMONIAGENESIS: 15NH3 STUDIES WITH GC-MS

肾氨生成：使用 GC-MS 进行 15NH3 研究

基本信息

批准号：
3233010
负责人：
ITZHAK NISSIM
金额：
$ 16.41万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
1984
资助国家：
美国
起止时间：
1984-12-01 至 1991-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3233010
关键词：
acid base balance acidity /alkalinity acidosis alkalosis alpha ketoglutarate aminoacid metabolism ammonia citrate synthase gluconeogenesis glucose glutamate ammonia ligase glutamate dehydrogenase glutamates homeostasis kidney metabolism laboratory rat mass spectrometry radiotracer

项目摘要

This proposal entails a comprehensive examination of the mechanism(s) controlling renal amino acid metabolism, ammoniagenesis and gluconeogenesis in various acid base states. The work will address five primary themes: (1) the metabolic signals initiating augmented ammoniagenesis in acidosis; (2) the rate limiting metabolic pathway(s) for ammonia production; (3) the role of effectors and/or inhibitors of ammoniagenesis on the underlying biochemistry; (4) the putative relationship between renal ammonia and glucose formation; (5) the biochemical adaptation occurring both during the induction of and recovery from acidosis and alkalosis. The core hypothesis of the work is that diminished flux through the citrate synthetase pathway is an initial step in a coordinated sequence of events leading to an increased rate of ammoniagenesis in acidosis. A corollary hypothesis is that the diminution of the alpha-ketoglutarate pool secondary to reduced flux through citrate synthetase is accompanied by enhanced flux through glutamate dehydrogenase toward oxidative deamination of glutamate with the release of NH3. We also will explore the possibility that the augmentation of ammoniagenesis and gluconeogenesis in acidosis are (or are not) inter-dependent phenomenon subject to common metabolic signals and controls, with the increase of glucose production providing an outlet for glutamate carbon. The significance of diminished flux through the glutamine synthetase reaction in abetting HN3 production will be studied as well. These topics will examined by incubating isolated rat renal tubules with 15N and/or 13C labelled precursors in the presence and absence of metabolic modulators and/or inhibitors. Subsequent determination of important precursor-product relationships and flux rates will be made using gas chromatography-mass spectrometry and/or nuclear magnetic resonance spectroscopy. The data so obtained will be of scientific import by deepening our understanding of renal ammoniagenesis in response to perturbations of hydrogen ion homeostasis. The project will evaluate such adaptations in terms of the stage of acidosis or alkalosis, i.e., during the induction of or recovery from either state.

该提案需要对控制肾氨基酸代谢的机制，在各种酸基态下的氨化和糖异生。这项工作将解决五个主要主题：（1）代谢信号引发了酸中毒的增强氨（增强氨（氨）；（2）用于氨产生的代谢途径的速率限制；（3）效应子和/或氨（氨（氨）抑制剂在基础生物化学；（4）推定的关系肾氨和葡萄糖形成；（5）生化在诱导和恢复期间进行适应来自酸中毒和碱性病。这项工作的核心假设是通过柠檬酸酸合成酶途径的通量减少是在一系列事件序列中的第一步，导致酸中毒中的氨（氨化速率）增加。推论假设是α-Ketoglutarate池的减少继发于通过柠檬酸酸酯合成酶减少的通量为伴随着通过谷氨酸脱氢酶增强的通量通过释放的谷氨酸氧化脱氨 NH3。我们还将探讨增强的可能性酸中毒中的氨（或不）相互依存的现象受到常见代谢信号的影响和控制，随着葡萄糖产生的增加提供了谷氨酸碳的出口。通量减少的意义通过谷氨酰胺合成酶在教tting HN3中的反应也将研究生产。这些主题将通过孵育孤立的大鼠肾脏来检查在存在下标记为15N和/或13C的小管没有代谢调节剂和/或抑制剂。随后确定重要的前体产品关系和通量率将使用气体建立色谱 - 质谱法和/或核磁共振光谱。如此获得的数据将是科学的通过加深我们对肾脏氨（肾脏氨（in）的理解对氢离子稳态扰动的反应。这项目将根据阶段评估此类适应酸中毒或碱中毒，即从诱导或从任何一个状态。