Figure 1.

Glucose-stimulated insulin secretion in pancreatic β-cells. (Left) When plasma glucose is low, the decreased ratio of ATP/Mg-ADP will increase K_ATP channel opening. Consequently, the cell membrane is hyperpolarized, preventing voltage-gated calcium channel opening, Ca²⁺ influx, and insulin secretion. (Right) When plasma glucose is high, glucose is transported into the cell via GLUT2. Glucose metabolism leads to an increased ratio of ATP/Mg-ADP, resulting in K_ATP channel closure, membrane depolarization, opening of voltage-gated calcium channels, Ca²⁺ influx, and insulin secretion.