STUDIES ON GLYCOGEN SYNTHESIS & GLUCONEOGENESIS

糖原合成的研究

• 批准号: 3234853
• 负责人: JOSEPH KATZ
• 金额: $ 25.75万
• 依托单位: CEDARS-SINAI MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-12-15 至 1993-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3234853
• 关键词: Krebs' cycle; diet; gas chromatography; gas chromatography mass spectrometry; gluconeogenesis; glucose metabolism; glycogen; glycogenesis; hormone regulation /control mechanism; laboratory rat; liver metabolism; muscle metabolism; nutrition related tag; radiotracer; tritium

Glycogen in liver may be synthesized either directly from glucose or indirectly from lactate and alanine, which are cleavage products of glucose in nonhepatic tissues and which are returned to liver. We are developing methods to measure the contribution of these pathways to glycogen in the intact animal (rat) by using radioactive and nonradioactive tracers. The radioactive tracer used here is water labeled with tritium (3HOH). The incorporation of labeled hydrogen on carbons 2 and 6 of glucose provides an estimate of these pathways that is much more reliable than with 14C labeled substrates. Another method to measure the pathways of glycogen is by using nonradioactive carbon (13C). Glucose labeled uniformly with 13C (U-13C) will be infused intragastrically in rats. Liver glycogen will be isolated and assayed by gas liquid-mass spectroscopy to obtain the distribution of masses from 181 to 186 (1 to 6 labeled carbons per molecule). The ratio of glucose of mass 186 to that of all labeled molecules provides an estimation of the direct pathway. This method also does not depend on the specific activity of precursors and attainment of steady state. The use of labeled substrates and mass spectroscopy to study glycogen and glucose synthesis and the operation of the Krebs cycle will be explored. The value of the use of nonradioactive tracers such as 13C is that ultimately these procedures can be applied to humans without risks due to radioaction damage.

肝脏中的糖原可以直接由葡萄糖合成 或间接来自乳酸盐和丙氨酸，它们是裂解产物 非肝组织中的葡萄糖并返回肝脏。 我们正在开发方法来衡量这些贡献 完整动物（大鼠）中糖原的途径 放射性和非放射性示踪剂。 放射性示踪剂 这里使用的是标有氚 (3HOH) 的水。 公司成立 葡萄糖的碳 2 和碳 6 上的标记氢提供了 这些路径的估计比 14C 更可靠 标记的底物。 另一种测量糖原途径的方法是使用 非放射性碳（13C）。 13C 统一标记的葡萄糖 (U-13C)将被注入大鼠胃内。 肝糖原 将通过气液质谱分离和分析 获取从 181 到 186 的质量分布（1 到 6 标记为 每个分子的碳数）。 质量为186的葡萄糖与该物质的比例 所有标记分子提供了直接估计 途径。 该方法也不依赖于特定的活动 前体的数量和稳定状态的实现。 标签的使用 研究糖原和葡萄糖的底物和质谱 将探索克雷布斯循环的合成和操作。 使用 13C 等非放射性示踪剂的价值在于 最终这些程序可以毫无风险地应用于人类 由于放射性损伤。