Fig. 1.

Physiological regulation of glucose in a healthy cell (A) and pathophysiological differences between the T1 (B) and T2 (C) DM. In healthy cells (A), glucose is transported into the cells using GLUT4 in the presence of insulin. When blood glucose levels rise, insulin is released and binds to its receptor on the cell surface. This activates a series of events leading to translocation of GLUT4 transporters to the cell surface. With GLUT4 transporters now present in the membrane, glucose can bind to them and enter the cell. However, in the T1DM (B), the lack of insulin production or absence of insulin prevents the proper translocation of GLUT4 transporters to the cell surface. Without sufficient insulin, GLUT4 remains trapped inside intracellular vesicles, impairing glucose uptake into cells. This leads to elevated blood glucose levels. In T2DM, insulin resistance can disrupt the transport of glucose inside cells using GLUT4. Insulin resistance reduces the effectiveness of insulin in promoting glucose uptake, thus, decreases glucose uptake into cells, leading to elevated blood glucose levels. GLUT4, glucose transporter 4; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus.