Wischeler B S, Müller-Ruchholtz E R, Reinauer H
Pflugers Arch. 1975 Mar 22;355(1):27-37. doi: 10.1007/BF00584797.
In isolated guinea pig hearts performing a defined stroke work, the influence of heart work and substrate uptake on the interconversion of pyruvate dehydrogenase (PDH) was studied. When hearts from fasted animals are perfused with a salt solution containing 10mM glucose, an increase in cardiac output and aortic pressure effects an increase in active PDH from 50 to 74% of total PDH activity and a decrease in tissue content of energy-rich phosphates. Pyruvate turnover calculated from oxygen consumption corresponds with PDH activity. Under these experimental conditions, PDH activity might either represent the rate limiting step of oxidative glucose breakdown, or it might be adjusted to a flux rate controlled by other factors. In fed animals, PDH activity exceeds the pyruvate turnover. However, an increase of heart work raises the active PDH from 76 to 95%. Addition of 10 mM acetate to the perfusion medium decreases PDH activity and glucose uptake. In fed animals, an increase of heart work raises the active PDH from 43 to 59% only, whereas in fasted animals this effect is abolished. The effect of changes in heart work on PDH interconversion might be explained by changes in energy-rich phosphate concentrations. However, substrate uptake and nutritional state may interfere or even abolish this effect.
在进行特定搏功的离体豚鼠心脏中，研究了心脏作功和底物摄取对丙酮酸脱氢酶（PDH）相互转化的影响。当用含10mM葡萄糖的盐溶液灌注禁食动物的心脏时，心输出量和主动脉压的增加会使活性PDH从总PDH活性的50%增加到74%，并使富含能量的磷酸盐的组织含量降低。根据耗氧量计算的丙酮酸周转率与PDH活性相对应。在这些实验条件下，PDH活性可能代表氧化葡萄糖分解的限速步骤，或者它可能被调整到由其他因素控制的通量率。在喂食的动物中，PDH活性超过丙酮酸周转率。然而，心脏作功的增加会使活性PDH从76%提高到95%。向灌注培养基中添加10mM乙酸盐会降低PDH活性和葡萄糖摄取。在喂食的动物中，心脏作功的增加仅使活性PDH从43%提高到59%，而在禁食动物中这种作用则被消除。心脏作功变化对PDH相互转化的影响可能由富含能量的磷酸盐浓度的变化来解释。然而，底物摄取和营养状态可能会干扰甚至消除这种作用。
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