Sako E Y, Kingsley-Hickman P B, From A H, Ugurbil K, Foker J E
Department of Surgery, University of Minnesota, Minneapolis.
J Surg Res. 1988 Apr;44(4):430-5. doi: 10.1016/0022-4804(88)90186-2.
A study was undertaken to examine the effects of glucose versus pyruvate as the sole substrate following severe myocardial ischemia. Glycolysis usually contributes only a small amount to total ATP production and may be rate limiting in providing tricarboxylic acid (TCA) cycle substrates. Consequently, pyruvate may be a more effective substrate by bypassing glycolysis to feed directly to the TCA cycle and oxidative phosphorylation. Isolated rat hearts were studied in a retrograde (Langendorff) perfusion apparatus while in an NMR spectrometer. Rate pressure product (RPP), myocardial oxygen consumption (MVO2), and the unidirectional Pi----ATP rate were measured in control and postischemic hearts with or without the inotrope dobutamine. The undirectional Pi----ATP rate was higher in the glucose than the pyruvate hearts and the difference increased further postischemia. This increase over that of the pyruvate hearts has been attributed to a glycolytic component of ATP metabolism. Oxygen consumption was higher in pyruvate hearts at equivalent levels of performance. It thus appears that the glycolysis rate is significant and may be elevated following severe myocardial ischemia. Perfusion with pyruvate requires increased rates of oxidative phosphorylation to make up for the loss of glycolytically produced ATP. Optimal postischemic substrate delivery may require several compounds, one of which should be glucose.
一项研究旨在探讨在严重心肌缺血后，以葡萄糖和丙酮酸作为唯一底物的效果。糖酵解通常对总ATP生成的贡献较小，且在提供三羧酸（TCA）循环底物方面可能是限速步骤。因此，丙酮酸可能是一种更有效的底物，它可绕过糖酵解直接进入TCA循环和氧化磷酸化过程。在处于核磁共振光谱仪中的逆行（Langendorff）灌注装置中对离体大鼠心脏进行研究。在有或没有正性肌力药物多巴酚丁胺的情况下，对对照心脏和缺血后心脏测量速率压力乘积（RPP）、心肌耗氧量（MVO2）以及单向磷酸根-ATP速率。葡萄糖组心脏的单向磷酸根-ATP速率高于丙酮酸组心脏，且缺血后这种差异进一步增大。相对于丙酮酸组心脏，这种增加归因于ATP代谢中的糖酵解成分。在同等性能水平下，丙酮酸组心脏的耗氧量更高。因此，似乎糖酵解速率很显著，并且在严重心肌缺血后可能会升高。用丙酮酸灌注需要提高氧化磷酸化速率以弥补糖酵解产生的ATP的损失。缺血后最佳的底物输送可能需要几种化合物，其中一种应该是葡萄糖。
