Anaplerotic and Oxidative Regulation of Hepatic Gluconeogenesis In Vivo

 描述(由申请人提供)：这个项目是一个F32博士后奖学金，旨在加强候选人在应用稳定同位素示踪技术测量代谢流量方面的培训。肝脏胰岛素抵抗会导致肝脏糖异生不适当地升高，并激活肝脏TCA循环的某些途径。这些影响通过增加血糖而导致糖尿病，也可能通过影响氧化代谢而与肝病相互作用。TCA循环是糖异生和肝脏能量代谢的中心途径。它位于线粒体中，通过其氧化功能和糖异生、脂肪酸合成所需的中间产物提供能量，并通过其逆转录功能提供氨基酸。线粒体功能受损与肝脏胰岛素抵抗有关。我们实验室最近的研究结果表明，肝脏胰岛素抵抗会刺激TCA循环中的失活和氧化代谢。目前尚不清楚TCA循环通量增加是糖异生增加的原因还是影响。为了解决这个问题，我们将特别干扰TCA循环的氧化功能和抗逆功能 条件性小鼠遗传学。将结合基于稳定同位素示踪剂的核磁共振和质谱学技术来研究这两种途径的作用，以测量代谢通量。这些途径对肝脏胰岛素抵抗的必要性将在正常和高脂肪饮食中进行测试。我们假设，破坏TCA循环的抗逆或氧化功能将减少肝脏的糖异生，从而减轻肝脏胰岛素抵抗的严重程度。这些研究将作为一个脚手架 对应聘者进行代谢流方法的应用培训。

 DESCRIPTION (provided by applicant): This project is an F32 postdoctoral fellowship designed to enhance the candidate's training in the application of stable isotope tracer techniques to measure metabolic flux. Hepatic insulin resistance results in inappropriately elevated gluconeogenesis in the liver and activation of certain pathways of the hepatic TCA cycle. These effects contribute to diabetes by increasing blood glucose and also perhaps interact with liver disease by impinging on oxidative metabolism. The TCA cycle is a central pathway of both gluconeogenesis and hepatic energy metabolism. It is located in mitochondria and provides energy through its oxidative function and intermediates required for gluconeogenesis, fatty acid synthesis, and amino acid production through its anaplerotic function. Impaired mitochondrial function has been linked to hepatic insulin resistance. Recent results from our laboratory have shown that hepatic insulin resistance stimulates both anaplerosis and oxidative metabolism in the TCA cycle. Whether increased TCA cycle flux is a cause or an effect of increased gluconeogenesis remains unknown. To address this question, we will specifically disrupt the oxidative function and anaplerotic function of the TCA cycle using conditional mouse genetics. The role of these two pathways will be examined using a combination of stable isotope tracer-based nuclear magnetic resonance and mass spectrometry techniques to measure metabolic flux. The necessity of these pathways for hepatic insulin resistance will be tested in normal and high fat diets. We hypothesize that disrupting the anaplerotic or oxidative function of the TCA cycle will reduce hepatic gluconeogenesis and therefore reduce the severity of hepatic insulin resistance. These studies will serve as a scaffold for the candidate to train in the application of metabolic flux approaches.