• GLUT-1 contributes to basal glucose transport in erythrocytes and at the blood-brain barrier.
• GLUT-2 is present in hepatocytes, pancreatic beta cells, and at the basolateral membrane of renal tubules and small intestinal mucosa. It plays a role in absorption of dietary glucose, reabsorption of glucose from renal tubules, hepatic glucose regulation, and sensitivity of beta cells to circulating glucose.
• GLUT-3 is involved in placental and neuronal glucose transport.
• GLUT-4 is present in adipose tissue, and skeletal & heart muscle
  • Only one responsive to insulin
  • Plays a key role in regulating body glucose homeostasis
  • Insulin stimulates incorporation of GLUT4 (stored in vesicles) into plasma membranes of cells for controlled glucose uptake and storage.
  • Physical exercise also induces the translocation of GLUT4 into the plasma membrane of skeletal muscle, in an insulin-independent manner.
• GLUT-5 is a fructose transporter found in spermatocytes and the gastrointestinal tract.