Effect of Exercise and Insulin Signaling on Glucose Transporter Type 4 in Skeletal Muscles: A narrative review

Abstract

Introduction: Glucose transporter type 4 (GLUT4) is a membrane glucose transporter that is influenced by insulin signaling and muscle contraction. The aim of the present study was to review the function of GLUT4 in normal conditions and insulin resistance, as well as the role of exercise training on the kinetics of GLUT4 in skeletal muscles. In the present study, by searching for sports keywords; exercise; sports adaptations; glucose transporter; absorption of glucose; glucose transporter type 4; type 2 diabetes; insulin signaling; and insulin resistance was searched from electronic databases of related articles until November 2022 and entered into the study.
 Conclusion: Due to the pathological factors of type 2 diabetes, skeletal muscles are disturbed in the delivery, absorption, and metabolism of glucose; pathological disorders of muscle tissue affect insulin signaling and the quantity and function of GLUT4. In the present review, it was found that an exercise training session initiated the GLUT4 gene expression and protein production and its transfer from intracellular stores to sarcolemma; this effect of local exercise was related to muscle contraction. GLUT4 gene and protein expression increased in response to regular exercise and led to an increase in the total level of GLUT4 protein in skeletal muscles; furthermore, regular exercise has improve insulin signaling and, as a result, improved muscle efficiency for blood glucose collection. Considering the role of physical activity on muscle function in blood glucose collection, one of the treatment goals in type 2 diabetes is maintaining muscle mass, increasing muscle mass and also increasing muscle function (muscle quality).