Patel T B, Olson M S
Am J Physiol. 1984 Jun;246(6 Pt 2):H858-64. doi: 10.1152/ajpheart.1984.246.6.H858.
The effect of flow-induced ischemia on the rate of pyruvate decarboxylation and the activation state of the pyruvate dehydrogenase multienzyme complex was investigated in the isolated, perfused rat heart. Pyruvate dehydrogenase activity in the heart decreased significantly during flow-induced ischemia and was a function of changes in the activation state (i.e., active/total activity) of the enzyme complex. In the absence of pyruvate, the activation state of pyruvate dehydrogenase decreased from nearly 100% active at the normal flow rate (10 ml/min) to 20% active as the flow was reduced to 0.5 ml/min. At high pyruvate levels (5 mM), the activation state increased from nearly 70% active at control flow rates to 100% active during ischemia. At an intermediate pyruvate concentration (0.5 mM), the enzyme complex was maintained at a relatively low activation state (30-35% active) throughout the range of flow rates tested. Ischemia caused elevated perfusate lactate concentrations only when the flow rates were less than 5.0 ml/min. The activation state of the pyruvate dehydrogenase complex in hearts perfused with glucose was also decreased during ischemia.
在离体灌注大鼠心脏中，研究了血流诱导的缺血对丙酮酸脱羧速率和丙酮酸脱氢酶多酶复合体激活状态的影响。在血流诱导的缺血过程中，心脏中的丙酮酸脱氢酶活性显著降低，并且是该酶复合体激活状态（即活性/总活性）变化的函数。在没有丙酮酸的情况下，丙酮酸脱氢酶的激活状态从正常流速（10毫升/分钟）时的近100%活性降低到血流降至0.5毫升/分钟时的20%活性。在高丙酮酸水平（5毫摩尔）下，激活状态从对照流速时的近70%活性增加到缺血期间的100%活性。在中等丙酮酸浓度（0.5毫摩尔）下，在测试的整个流速范围内，酶复合体维持在相对较低的激活状态（30 - 35%活性）。仅当流速小于5.0毫升/分钟时，缺血才会导致灌注液中乳酸浓度升高。在用葡萄糖灌注的心脏中，丙酮酸脱氢酶复合体的激活状态在缺血期间也会降低。
