Exercise and GLUT4 in human subcutaneous adipose tissue

To examine the effect of acute and chronic exercise on adipose tissue GLUT 4 expression, a total of 20 healthy, male subjects performed one of two studies. Ten subjects performed cycle ergometer exercise for 60 min at 73 ± 2% VO 2 peak and abdominal adipose tissue samples were obtained immediately before and after exercise and after 3 h of recovery. Another 10 subjects completed 10 days of exercise training, comprising a combination of six sessions of 60 min at 75% VO 2 peak and four sessions of 6 × 5 min at 90% VO 2 peak, separated by 3 min at 40% VO 2 peak. Abdominal adipose tissue and vastus lateralis muscle samples were obtained before training and 24 h after the last training session. A single bout of exercise did not change adipose tissue GLUT 4 mRNA ; however, there was a small, but significant, reduction in adipose tissue GLUT 4 protein expression 3 h after exercise. There were no changes in adipose tissue GLUT 4 or COX ‐ IV expression following exercise training. In contrast, skeletal muscle GLUT 4 and COX ‐ IV were increased by 47% and 44%, respectively following exercise training. The exercise training‐induced increase in GLUT 4 expression was similar in both type I and type II a single muscle fibers. Our results indicate that neither a single exercise bout, nor 10 days of exercise training, increased adipose tissue GLUT 4, in contrast with the increases observed in skeletal muscle GLUT 4 expression.