the release of the protein insulin from pancreatic cells occurs by
Insulin signal transduction pathway Glucose gets converted to Glucose-6-Phosphate (G6P) through Glucokinase; and G6P is subsequently oxidized to form ATP. This process inhibits the ATP-sensitive potassium ion channels of the cell causing the Potassium ion channel to close and not function anymore. The closure of the ATP-sensitive potassium channels causes depolarization of the cell membrane causing the cell membrane to stretch which causes the voltage-gated calcium channel on the membrane to open causing an influx of Ca2+ ions. This influx then stimulates fusion of the insulin vesicles to the cell membrane and secretion of insulin in the extracellular fluid outside the beta cell; thus making it enter the bloodstream. [Also Illustrated in Figure 1.1.1].[2]
Pancreatic islets It has been recognized that the cytoarchitecture of pancreatic islets differs between species.[8][9][10] In particular, while rodent islets are characterized by a predominant proportion of insulin-producing beta cells in the core of the cluster and by scarce alpha, delta and PP cells in the periphery, human islets display alpha and beta cells in close relationship with each other throughout the cluster.[8][10]