Preferential oxidation of glycogen in isolated working rat heart.
Preferential oxidation of glycogen in isolated working rat heart.
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离体工作大鼠心脏中糖原的优先氧化。
DOI：
10.1172/jci118561
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Taegtmeyer,H
中科院分区：
文献类型：
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作者：
Goodwin,GW;Ahmad,F;Taegtmeyer,H
我们测试的假设，糖原优先氧化在离体工作大鼠心脏。这是通过测量糖酵解通量的比例（氧化加上乳酸盐的产生），特别是从糖原代谢成乳酸盐，并将其与肾上腺素刺激期间从外源性葡萄糖同时测定的相同比例进行比较来实现的。用14 C或3 H预标记糖原后，使用双同位素技术同时追踪糖原和外源性葡萄糖在氧化和非氧化途径之间的分布。在加入肾上腺素（1 μ M）后，立即将40-50%的葡萄糖通量导向乳酸盐。然而，糖原几乎完全被氧化，对乳酸没有贡献。此外，糖原利用率迅速响应肾上腺素的收缩性能的突然增加，在利用外源性葡萄糖的刺激滞后期间，这表明糖原作为底物水库缓冲需求的快速增加。糖原的优先氧化可用于确保从有限供应的内源性底物有效产生ATP，或作为在快速糖原分解期间限制乳酸积累的机制。
We tested the hypothesis that glycogen is preferentially oxidized in isolated working rat heart. This was accomplished by measuring the proportion of glycolytic flux (oxidation plus lactate production) specifically from glycogen which is metabolized to lactate, and comparing it to the same proportion determined concurrently from exogenous glucose during stimulation with epinephrine. After prelabeling of glycogen with either 14C or 3H, a dual isotope technique was used to simultaneously trace the disposition of glycogen and exogenous glucose between oxidative and non-oxidative pathways. Immediately after the addition of epinephrine (1 microM), 40-50% of flux from glucose was directed towards lactate. Glycogen, however, did not contribute to lactate, being almost entirely oxidized. Further, glycogen utilization responded promptly to the abrupt increase in contractile performance with epinephrine, during the lag in stimulation of utilization of exogenous glucose, suggesting that glycogen serves as substrate reservoir to buffer rapid increases in demand. Preferential oxidation of glycogen may serve to ensure efficient generation of ATP from a limited supply of endogenous substrate, or as a mechanism to limit lactate accumulation during rapid glycogenolysis.