The Effects of Hyperglycemia and Hyperlipidemia on Muscle Glycogen Utilization during Exercise in rats

Ahn, Jong Chul; Lee, Dong Woo; Shon, Oog Jin; Lee, Seuk Kang

Abstract

The effects of hyperglycemia and hyperlipidemia on utilization of muscle glycogen during 45 minutes treadmill running(26 m/min, 8 % grade) were evaluated in Sprague Dawley rats, and the charateristic of the 4 different type of muscles, soleus, white and red gastrocnemius, and plantaris, on glycogen utilization were simultameously investigated. Hyperglycemia, 145-165 mg/dL, was induced by oral glucose ingestion, and hyperlipidemia, 444 uEq/L, was induced by combined treatment of intraperitoneal heparine injection and oral 10 % intralipose ingestion. During the hyperglycemic trial, the glycogen utilization of plantaris muscle was decreased by 13 % at 45 minutes duration of treadmill running comparing to the control trial(p<0.05), and the glycogen utilization of white gastrocnemius was also decreased. The sparing tendency of soleus and red gastrocnemius by 5-13 % was observed at 30 and 45 minutes of treadmill running in hyperglycemic trial. There was no glycogen sparing effect of hyperlipidemia in the soleus, red gastrocnemius and plantaris muscle subjected in this experiment during exercise. However, only a slight sparing tendency of white gastrocnemius muscle was observed. In summary, the glycogen sparing effect of hyperglycemia during exercise was observed in plantaris and white gastrocnemius muscles in rats. However, there was no glycogen sparing effect of hyperlipidemia in the 4 hindlimb muscles. It was observed that the glycogen sparing effect of hyperglycemia is more prominant in fast glycolytic muscle fiber.