Which glucose transporter is responsible for transporting glucose in skeletal and cardiac muscle?

GLUT4 is the primary glucose transporter responsible for transporting glucose into skeletal and cardiac muscle cells. This transporter is unique because it is insulin-sensitive, meaning that its translocation to the cell membrane is regulated by insulin levels. When insulin binds to its receptors on muscle and adipose tissue, it promotes the movement of GLUT4-containing vesicles to the plasma membrane, increasing glucose uptake from the bloodstream into these cells.

In skeletal and cardiac muscles, this mechanism is crucial for maintaining glucose homeostasis, especially during periods of increased energy demand, such as exercise. The ability of GLUT4 to respond to insulin allows muscle cells to effectively utilize glucose as a source of energy, preparing them to meet metabolic needs.

The other glucose transporters mentioned have specific roles in different tissues. For instance, GLUT1 is primarily found in the blood-brain barrier and is essential for glucose transport to the brain; GLUT2 is found in the liver, kidney, and pancreatic beta cells, serving to facilitate the release of glucose; and GLUT3 is mainly expressed in neurons, where it plays a critical role in glucose uptake to support neuronal function. Each of these transporters has a distinct and important function, but GLUT4 is the only one that specifically mediates glucose transport in response to