Physical training attenuates phosphocreatine and long-chain acyl-CoA alterations in diabetic rat heart

This study was designed to assess the effect of physical training on high-energy phosphate levels in the heart of diabetic rats. Diabetes was induced with streptozocin (50 mg/kg), and exercise training was carried out on a treadmill with a progressive 10-wk program. Plasma glucose levels at the end of the training program showed only a small improvement of the diabetic state in trained animals (21.7 +/- 1.3 vs. 24.4 +/- 0.8 mmol/l; P < 0.05). The lower heart rate observed in sedentary diabetic rats (279 +/- 6 vs. 356 +/- 5 beats/min; P < 0.001) was improved by physical training (301 +/- 8 beats/min; P < 0.05 vs. sedentary diabetics). Significantly lower phosphocreatine levels were found in sedentary diabetic rats (12.0 +/- 0.7 mumol/g dry wt) than in sedentary control rats (15.0 +/- 0.9 mumol/g dry wt; P < 0.05) but not in trained diabetic rats (13.7 +/- 0.7 mumol/g dry wt). ATP levels were not affected by diabetes but were increased by training. The increased long-chain acyl-CoA levels in sedentary diabetic rats (146 +/- 7 vs. 119 +/- 8 mumol/g dry wt in sedentary control rats; P < 0.05) were improved by training (138 +/- 6 mumol/g dry wt; P > 0.05 vs. sedentary control rats). These data indicate that the diminution in phosphocreatine levels observed in the heart tissue of chronically diabetic rats can be attenuated by an exercise training program.