Pancreatic beta cells function primarily by sensing blood glucose levels. When blood glucose levels rise, beta cells respond by secreting insulin. Insulin facilitates the uptake of glucose by cells, particularly in the liver, muscle, and adipose tissue, thus lowering blood glucose levels. The process begins when glucose enters the beta cells via GLUT2 transporters. Inside the cells, glucose undergoes metabolism to produce ATP, which leads to the closure of ATP-sensitive potassium channels. This causes depolarization of the cell membrane, opening voltage-gated calcium channels. The influx of calcium triggers the exocytosis of insulin-containing granules.
