In skeletal muscle, some of the glucose is converted to glycogen and stored. Figure 4.4 . Glucose transport from the gastrointestinal tract to the circulating blood. Glucose uptake by skeletal muscle cells. Glucose is carried to muscle in the blood.
Glucose diffuses out of the blood vessels to the muscle cells.
Glucose enters muscle cells by a carrier-mediated mechanism. In skeletal muscle, the transporter is responsive to insulin, an enzyme made in the pancreas. Insulin causes glucose transport proteins, stored in the cell cytoplasm, to be inserted in the plasma membranes of these cells. This process enhances glucose entry for glycolysis or glycogen synthesis. Insulin is the single most important controller of organic metabolism.