1991 Volume 34 Issue 4 Pages 293-300
31P nuclear magnetic resonance spectroscopy was used to assess the effects of diabetes control on skeletal muscle metabolism during ischemic contraction. The relative concentrations on inorganic phosphate (Pi), phosphocreatine (PCr) and ATP in hamstring muscles were measured, along with intracellular pH, at rest, during ischemic exercise and in the subsequent recovery period. Ischemic exercise resulted in a severe reduction of PCr and fall in pH in diabetic patient. The time required to resynthesize ATP during the recovery period, as measured by the time required to replete PCr after exercise, was significantly lower in diabetic patients. The Pi peak was split during ischemic exercise in patients whose diabetic control was poor. This could be accounted for on the basis of differential recruitment of glycolytic and oxidative fibers or muscle oxidative capacity. Correction of blood suger led to correction of these metabolic abnormalities. These results indicate that energy production via oxidative metablolism is impaired but glycolysis may be increased in diabetic patients with poor control. These changes can not be explained by impaired blood flow or oxygen delivery. These observations suggest that exertional fatigue in diabetic patients with poor control may, in part, be the result of severe PCr depletion and /or acidosis in working muscle.
