GLP-1

Glucagon-like peptide-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) activated by glucagon-like peptide-1 (GLP-1) that regulates glucose-dependent insulin secretion and metabolic homeostasis^[1][2]. GLP-1R activation stimulates adenylate cyclase activity, increases intracellular cyclic AMP (cAMP), and activates downstream signaling pathways including protein kinase A (PKA) and exchange protein directly activated by cAMP (EPAC)^[2][3]. Mechanistically, GLP-1R signaling enhances pancreatic β-cell insulin secretion, regulates glucagon release, and influences gastrointestinal and central nervous system functions^[1][4]. In disease models, impaired GLP-1R signaling is associated with metabolic disorders including type 2 diabetes mellitus and obesity, where GLP-1R agonists improve glucose control and regulate energy balance^[4][5]. GLP-1R agonist treatment promotes glucose-dependent insulin secretion and reduces body weight through coordinated effects on pancreatic, gastrointestinal, and central metabolic pathways^[5][6]. Compared with related class B GPCRs such as glucagon receptor (GCGR) and glucose-dependent insulinotropic polypeptide receptor (GIPR), GLP-1R has distinct ligand specificity and physiological functions mediated by GLP-1 signaling^[2][7]. For experimental applications, GLP-1R function is investigated using receptor expression systems, β-cell models, animal models, and pharmacological activation approaches^[1][6]. Synthetic GLP-1R agonists, including exendin-4 and long-acting GLP-1 analogs, are widely used to study receptor signaling and metabolic regulation^[6][8].