| Articles : Effects of Pre-Exercise Fasting and Feeding on Metabolic Substrates and Insulin in fasting blood and GLUT-4 in Soleus Muscle of Rats |
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| Abstract |
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This study was to investigate the effects of feeding and fasting prior to an exercise session on the blood metabolic substrates including glucose, free fatty acid, and lipase and on the expression of glucose transporter protein 4 (GLUT-4) in coleus muscle of the Sprague-Dawley rats. A total of 28 rats were randomly divided into the four following groups (each group: n = 7); fasting group (Fa group), fasting plus exercise group (FaE group), feeding group (Fe group), and feeding plus exercise group (FeE group). Each animal in the fasting groups was forced to fast for 14 hours. Each animal in the exercise groups was also forced to perform a treadmill running (speed: 18 m/min, 0% grade) for sixty minutes. Food was provided to the feeding groups 2 hours before the treadmill running. All the rats were sacrificed immediately after their treadmill running. Blood samples were collected for the analyses of lipase, glucose, FFA, insulin in circulating blood, and soleus muscle for the GLUT-4 expression. Both of the Fa and FaE groups had the lowest blood insulin concentration (p≤.001). The FaE group also had the lowest level of the GLUT-4 expression while the FeE group had the highest level of the GLUT-4 expression (p≤.05). the correlation between GLUT-4 and insulin was significantly higher in the resting condition than in the exercise condition. These current findings suggest that muscle GLUT-4 expression following acute exercise can be influenced by both feeding and fasting conditions. |
| Key Words:
Feeding, fasting, insulin, acute exercise, GLUT-4 |
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