Quantitative measurement of whole-body glycogen metabolism and gluconeogenic flux

项目概要/摘要 内源性葡萄糖产生失调是2型糖尿病的主要原因。最近出版的作品 来自申办方实验室的研究确定，乳酸盐携带最高的循环周转通量， 重要TCA底物。在这些研究中，通过静脉输注13 C- 在自由活动的小鼠中，葡萄糖在所有组织中的糖酵解中间体的标记都令人惊讶地低， 和禁食小鼠。如果不是循环葡萄糖，糖酵解中间产物的来源是什么？我们有两 假设：1）糖酵解中间产物来自糖原，2）糖原异生产生组织糖酵解 中间体的如果这两种情况中的任何一种是正确的，那么这些途径在更多的组织中比在其他组织中更频繁地活跃。 以前认为。在这里，我们将利用最先进的LC-MS代谢组学与静脉内 输注13 C-代谢物示踪剂，以测量进食和禁食小鼠在各种组织中的这些途径。 LC-MS在测量通过这些途径的通量时具有优势，包括1）测量 标记糖酵解中间体和2）确定定量标记模式。利用该 方法学，我们的目标是全面了解糖原代谢和糖原合成， 组织中这项工作不仅将加深我们对这些重要的代谢途径的理解，而且它具有 有可能揭示这些途径在维持组织和生物体健康方面的新作用。

Project Summary/Abstract Dysregulated endogenous glucose production is the central cause of type 2 diabetes. Recently published work from the lab of the sponsor determined that lactate carries the highest circulatory turnover flux and is an important TCA substrate. During these studies, a general observation made from intravenous infusion of 13C- glucose in freely moving mice was surprisingly low labeling of glycolytic intermediates in all tissues in both fed and fasted mice. What is the source of glycolytic intermediates if not circulating glucose? We have two hypotheses: 1) glycolytic intermediates come from glycogen and 2) gluconeogenesis produces tissue glycolytic intermediates. If either of these are true, these pathways are active more often and, in more tissues, than previously thought. Here, we will utilize state of the art LC-MS metabolomics in combination with intravenous infusion of 13C-metabolite tracers to measure these pathways in fed and fasted mice in a wide array of tissues. LC-MS offers advantages when measuring flux through these pathways including the ability to 1) measure labeling in glycolytic intermediates and 2) to determine quantitative labeling patterns. Utilizing this methodology, we aim to gain a comprehensive understand of glycogen metabolism and gluconeogenesis in all tissues. This work will not only deepen our understanding of these important metabolic pathways, but it has the potential to uncover novel roles for these pathways in maintaining tissue and organismal health.