Insulin release pathway

The insulin release pathway, also known as the glucose-stimulated insulin secretion (GSIS) pathway, is a critical signaling cascade in pancreatic beta cells that regulates insulin exocytosis to maintain blood glucose homeostasis. It begins with glucose entry via GLUT2 transporters, followed by glycolysis and ATP production, which closes ATP-sensitive KATP channels (Kir6.2/SUR1), causing membrane depolarization. This opens voltage-gated calcium channels (primarily L-type, with R-type in second phase), triggering calcium influx and vesicle fusion for biphasic insulin release. Dysregulation contributes to diabetes, with impaired GSIS in type 2 diabetes due to beta-cell dysfunction and in type 1 from autoimmune beta-cell loss. Therapeutically, drugs like sulfonylureas target KATP channels to mimic glucose effects, while GLP-1 agonists potentiate the pathway via cAMP, though risks include hypoglycemia from non-nutrient-stimulated secretion. Key components include glucokinase (rate-limiting glycolysis), proinsulin processing enzymes (PC1/3, PC2, CPE), and exocytotic proteins like SNAREs and synaptotagmin. This pathway exemplifies metabolic-electrical coupling essential for postprandial glucose control.

Other names

Insulin secretion pathwayGlucose-stimulated insulin secretion (GSIS) pathwayTriggering pathway to insulin secretion

Sulfonylureas and meglitinides close ATP-sensitive potassium (KATP) channels (Kir6.2/SUR1), leading to depolarization, calcium influx, and insulin exocytosis; GLP-1 agonists enhance cAMP/PKA signaling to amplify glucose-stimulated insulin secretion