[The role of skeletal muscle in the regulation of glucose homeostasis].

Muscle tissue has been considered to be a major regulator of systemic glucose homeostasis. Glucose normally provides energy sources for tissues of the body. Its uptake by muscle requires a secretion of insulin. The initial step of glucose utilization requires the transport of glucose into the cells. The insulin-receptor complex stimulates the cellular uptake of glucose. In the well-fed state muscle contains about 1% of its weight as glycogen. Because of its mass, muscle contains almost four times as much glycogen as the liver. Muscle glycogen is not directly available as a source of blood glucose because muscle lacks glucose-6-phosphatase. During muscular activity, glycogen is converted to lactate and then into blood glucose in the liver.