Ohlen J, Siess E A, Löffler G, Wieland O H
Diabetologia. 1978 Feb;14(2):135-9. doi: 10.1007/BF01263452.
Evidence is presented for regulation by insulin of pyruvate dehydrogenase (pdh) interconversion in rat heart muscle in vivo and in vitro. In the alloxan diabetic rat the active (dephospho) enzyme amounted only to 12% of total PDH and was restored to 42% by insulin. Antilipolytic treatment of the dibetic animals was ineffective, indicating that the action of insulin was independent of a lowering of plasma non-esterified fatty acid concentration. On perfusion of isolated hearts from diabetic rats in the presence of glucose the proportion of pyruvate dehydrogenase in the active form remained low but was fully restored upon addition of insulin (2mU/ml) to the medium. No effect of insulin was obtained in the absence of glucose. The correlation between the rate of pyruvate decarboxylation in the perfused heart and of pyruvate dehydrogenase activity, in vitro, suggests that in the diabetic heart the entry of pyruvate into the citric acid cycle is largely controlled by covalent modification of the pyruvate dehydrogenase complex rather than by feedback inhibition. The possible role of insulin therein is discussed.
有证据表明，胰岛素在体内和体外均可调节大鼠心肌中丙酮酸脱氢酶（PDH）的相互转化。在四氧嘧啶糖尿病大鼠中，活性（去磷酸化）酶仅占总PDH的12%，而胰岛素可将其恢复至42%。对糖尿病动物进行抗脂解治疗无效，这表明胰岛素的作用与血浆非酯化脂肪酸浓度的降低无关。在葡萄糖存在的情况下，灌注糖尿病大鼠的离体心脏时，活性形式的丙酮酸脱氢酶比例仍然很低，但向培养基中添加胰岛素（2mU/ml）后可完全恢复。在没有葡萄糖的情况下，胰岛素没有作用。灌注心脏中丙酮酸脱羧速率与体外丙酮酸脱氢酶活性之间的相关性表明，在糖尿病心脏中，丙酮酸进入柠檬酸循环在很大程度上受丙酮酸脱氢酶复合物的共价修饰控制，而非反馈抑制。文中讨论了胰岛素在其中可能发挥作用。
