GPR19 is a G protein-coupled receptor that functions as a multifaceted regulator of metabolism, circadian rhythms, and aging-related processes 1. The receptor serves as a pseudo-orphan GPCR with adropin as its endogenous ligand 2, mediating metabolic control through adropin-dependent signaling pathways 3. GPR19 expression is distributed across neuroendocrine tissues including pancreatic islets, intestinal ganglia, and brain cortex 4, where it coordinates stress responses and DNA damage management at varying expression levels 1. Functionally, GPR19 activation by adropin inhibits fibroblast activation and fibrosis through deactivation of TGFβ/GLI1 signaling 5, while promoting mesenchymal-epithelial transition in breast cancer via ERK/MAPK pathway activation 2. In adrenocortical cells, GPR19-mediated adropin signaling inhibits steroidogenesis through TGF-β pathway activation 6. Clinically, GPR19 shows diagnostic and prognostic significance in neuroendocrine and lung tumors, with elevated expression correlating with improved patient survival in adenocarcinomas 4. The receptor's role in aging-associated pathology positions it as a potential therapeutic target for metabolic dysfunction, fibrotic diseases, and diabetes 7.