Regulation of skeletal muscle GLUT-4 expression by exercise and nutritional stimuli

Abstract

Skeletal muscle is the primary site of glucose uptake in humans. Glucose transport activity, which is the rate-limiting step in muscle glucose metabolism, is linearly related to the content of the GLUT-4 isoform of the glucose transporter. Therefore, the level of GLUT-4 in skeletal muscle may be an important determinant of whole-body glucose disposal. It has been well documented that long-term, low- to moderate-intensity endurance exercise training induces an increase in muscle GLUT-4 content. However, emerging evidence suggests that an adaptive increase in GLUT-4 occurs even after a single acute bout of exercise or high-intensity intermittent exercise training. Recent findings also indicate that nutritional status affects GLUT-4 expression in skeletal muscle. This review provides an overview of the effects of exercise and nutritional status on GLUT-4 content in skeletal muscle, and summarizes recent progress in elucidating the molecular regulation of muscle GLUT-4 gene expression by exercise and nutritional stimuli.

Keywords

• glut-4
• skeletal muscle
• exercise training
• alternate-day fasting
• high-fat diet