The effect of glucose,lactate and pyruvate on the dynamic adaptation of cardiac mitochondrial oxygen consumption

AIM: To understand the effect of exogenous carbon substrate on the dynamic regulation of cardiac oxidative phosphorylation. METHODS: Method of mean response time measurement of the myocardial mitochondrial O₂ consumption (t_mito) was developed by van Beek. Glucose, lactate, or pyruvate as carbon substrate respectively for myocardial energy supply was perfused in isolated rabbit hearts with Tyrode solution at 37℃. RESULTS: When heart rate was stepped up from 120 to 140 and 220 (beat·min^-1) respectively the t_mito. We have measured was: (6.3±1.0)s and (7.4±0.9) s for glucose; (5.4±1.2) s and (7.0±0.9) s for lactate; (4.0±0.7)s and (6.5±0.6) s for pyruvate (two way ANOVA, P＜0.05, compared with lactate and glucose). CONCLUSION: The transport of reducing equivalent into the mitochondrial matrix might be a limitation factor of dynamic adaptation of cardiac mitochondrial oxidative phosphorylation during fast changes in ATP utilization.