The Effect of Aerobic Exercise Training on Hepatic Glycogen Metabolism in Type 1 Diabetic Rats
Abstract
The purpose of this investigation was to determine if ten weeks of aerobic exercise training could increase hepatic glycogen storage in rats with Type 1 Diabetes Mellitus (T1DM) and whether elevated hepatic glycogen content is associated with alterations in glycogenic proteins and insulin signaling. Rats were divided into control-sedentary, control-exercised, T1DM-sedentary and T1DM-exercised groups. Animals from each group underwent a euglycemic-hyperinsulinemic clamp at the conclusion of the study. Exercise training consisted of treadmill running at 27m/min, 6% incline for 1hr, five days/week for ten weeks. T1DM rats had lower liver glycogen concentrations than control rats and glycogen was not increased with training. GS, GK and PEPCK protein contents were also increased in the T1DM groups. Insulin-clamp stimulated GSK phosphorylation was not different between treatments. These findings indicate that aerobic exercise training does not increase liver glycogen content in T1DM rats despite increases in glycogenic protein content and normal insulin signaling.