Anaplerotic and Oxidative Regulation of Hepatic Gluconeogenesis In Vivo

 描述（由申请人提供）：该项目是一个F32博士后奖学金，旨在加强候选人的培训，在应用稳定同位素示踪技术来测量代谢通量。肝脏胰岛素抵抗导致肝脏中不适当地升高的胰岛素生成和肝脏TCA循环的某些途径的激活。这些作用通过增加血糖而导致糖尿病，并且还可能通过影响氧化代谢而与肝脏疾病相互作用。TCA循环是肝脏能量代谢和新生血管生成的中心途径。它位于线粒体中，并通过其氧化功能提供能量，并通过其回补功能提供再生、脂肪酸合成和氨基酸产生所需的中间体。线粒体功能受损与肝脏胰岛素抵抗有关。我们实验室的最新结果表明，肝脏胰岛素抵抗刺激TCA循环中的回补和氧化代谢。TCA循环通量的增加是否是促异生作用增加的原因或影响仍不清楚。为了解决这个问题，我们将专门破坏TCA循环的氧化功能和回补功能， 条件小鼠遗传学这两种途径的作用将使用基于稳定同位素示踪剂的核磁共振和质谱技术相结合来测量代谢通量。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循环的回补或氧化功能将减少肝脏的胰岛素生成，从而降低肝脏胰岛素抵抗的严重程度。这些研究将作为一个支架 为候选人训练代谢通量方法的应用。

 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.