Insulin-independent muscle glucose uptake induced by exercise

Exercise and insulin and exercise are the most relevant stimulators of glucose transport in skeletal muscle. Glucose uptake in skeletal muscle during exercise involves acceleration of several processes compared to the resting state. The scientific literature hould put more emphasis on the role played by muscle contraction to enhance glucose uptake with insulin-independent mechanisms. Indeed, a search on Pub Med using the key words "contraction and glucose uptake and muscle" gives 566 reports, while a search using the key words "insulin and glucose uptake and muscle" cites 4156 publications (May,2009). This chapter describes extensively the mechanisms permitting the insulinindependent glucose uptake in response to muscle utilization during exercise. The muscle contraction stimulates GLUT4 translocation in the absence of insulin. There are different intracellular "pools" of GLUT4, one stimulated by insulin and one stimulated by exercise. The roles exerted by AMPK, AICAR, calcium, NO, glycogen and hypoxia in the glucose uptake during exercise are underlined. The consequences of these phenomena on human wellness are discussed. Furthermore, the scarce treatment of insulin-independent glucose uptake in scholastic textbooks is underlined, to induce authors to treat this important argument more extensively.