The pancreas plays a central role in glucose homeostasis through the coordinated secretion of hormones, primarily insulin, glucagon, somatostatin, and pancreatic polypeptide. Insulin, secreted by the beta cells of the islets of Langerhans, is the principal anabolic hormone, promoting glucose uptake, glycogen synthesis, lipid storage, and protein synthesis, while inhibiting gluconeogenesis and lipolysis. Its release is tightly regulated by blood glucose levels, incretin hormones, autonomic input, and circulating nutrients. In contrast, glucagon, secreted by alpha cells, serves as a counter-regulatory hormone that raises blood glucose by stimulating hepatic glycogenolysis and gluconeogenesis during fasting or hypoglycemia. Somatostatin, produced by delta cells, functions as a paracrine inhibitor, modulating the release of both insulin and glucagon, and regulating the secretion and motility of gastrointestinal hormones. Pancreatic polypeptide, secreted by PP cells (F cells), is involved in the regulation of exocrine pancreatic secretion and hepatic glycogen levels, and may influence appetite. The dynamic interplay of these hormones ensures metabolic balance under varying physiological conditions. Disruptions in this balance, such as in diabetes mellitus, result in significant metabolic derangements, underscoring the importance of pancreatic endocrine function. Understanding the physiology of insulin and other pancreatic hormones is critical for comprehending metabolic regulation and the pathogenesis of endocrine disorders. This abstract provides a concise overview of the cellular sources, regulatory mechanisms, and physiological roles of pancreatic hormones, highlighting their integrated function in maintaining glucose and energy homeostasis.
Pancreas, Insulin, Islet of Langerhans, Endocrine, Glucose, Glycogen
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