Impaired non-insulin mediated glucose uptake after downhill running in rats

To evaluate the effects of a single bout of exercise on non-insulin mediated glucose uptake in rats, hyperglycemic clamp tests were performed either 12 h after the rats were subjected to downhill running (90 min, -16 degrees incline, n = 10) or without any prior exercise (n = 10). Somatostatin (1.0 microgram/kg/min) was infused during clamps to suppress insulin secretion, while the serum glucose was clamped at a level of 200 mg/dl for 100 min. The serum insulin levels during the hyperglycemic clamp was maintained at basal levels. The non-insulin mediated glucose disposal rate was significantly decreased during clamp performed after downhill running (5.45 +/- 0.61 mg/kg/min) compared to the control conditions (9.63 +/- 0.32 mg/kg/min, P < 0.01). The creatine kinase level after downhill running (561 +/- 206 IU/l) was significantly higher than the control conditions (118 +/- 20 IU/l, P < 0.01). These results thus suggest that the muscle damage caused by downhill exercise, which predominantly consists of eccentric type, may therefore decrease the non-insulin mediated glucose uptake.