QUANTITATION OF INTERMEDIARY METABOLISM IN HEPATOCYTES

与底物孵育的肝细胞中碳流动的真实模型 含有葡萄糖、核糖、果糖、丙氨酸和醋酸酯的混合物 开发并用于获得代谢物流动的定量描述 在有无胰高血糖素的情况下。增进对……的了解 肝细胞中间代谢的结构组织，我们 将进行配对实验(存在和不存在 加压素)，其中添加了天冬氨酸和谷氨酸 底物混合物。这些实验不仅将提供进一步的 关于糖异生和尿生氨基酸的处理信息，但 将使后叶加压素的作用与那些 胰升糖素对整个代谢物沿主要代谢产物流动模式的影响 中间代谢途径。我们还打算孵化 用含有以下物质的底物混合物从禁食大鼠分离肝细胞 芥酸、油酸、十二酸、己酸、丙酸、醋酸酯、乳酸和 丙酮酸，其中一种底物在任何给定的情况下都标记有14C 长颈瓶。大约80个独立的标签流入CO2的测量， 葡萄糖，以及乙酰乙酸酯的1和2，3，4位，a 足够超过独立通量参数的数目 对提议的脂肪酸模型进行严格的测试 新陈代谢和β-氧化的定量估计 线粒体和过氧化体途径以及各自的欧米伽氧化 混合物中的脂肪酸。这些研究将延长：1) 用苯扎贝特处理的大鼠肝细胞分离， 已知的降血脂药物可增加过氧化物酶； 2)使用含有葡萄糖、核糖、果糖、 丙氨酸、醋酸盐、谷氨酸、油酸和芥酸 代谢产物沿代谢途径流动的定量描述 以上开发的组合模型。

A realistic model of carbon flow in hepatocytes incubated with a substrate mixture containing glucose, ribose, fructose, alanine, and acetate has been developed and used to obtain a quantitative description of metabolite flows in the presence and absence of glucagon. To increase our understanding of the structural organization of intermediary metabolism in hepatocytes, we will carry out paired experiments (in the presence and absence of vasopressin) in which aspartate and glutamate will be added to the above substrate mixture. These experiments will not only provide further information on the handling of gluconeogenic and ureagenic amino acids, but will allow quantitative comparison of the effects of vasopressin with those of glucagon on the entire pattern of metabolite flow along the major pathways of intermediary metabolism. We also intend to incubate hepatocytes isolated from fasted rats with a substrate mixture containing erucoate, oleate, dodecanoate, hexanoate, propioante, acetate, lactate, and pyruvate, with one of these substrates labeled with 14C in any given flask. Approximately 80 independent measurements of label flow into CO2, glucose, and the 1 and 2, 3, 4 positions of acetoacetate will be made, a number sufficiently in excess of the number of independent flux parameters to be computed to yield a stringent test of a proposed model of fatty acid metabolism and thus a quantitative estimate of Beta-oxidation in the mitochondrial and peroxisomal pathways and of Omega-oxidation for each of the fatty acids in the mixture. These studies will be extended by: 1) using hepatocytes isolated from rats treated with bezafibrate, a hypolipidemic drug known to increase peroxisomal Beta-oxidation enzymes; and 2) using a substrate mixture containing glucose, ribose, fructose, alanine, acetate, glutamate, oleic, and erucic acids to obtain a quantitative description of metabolite flow along the pathways of the combined models developed above.