Endocrine Pancreas and Glucose Metabolism

Abstract

Pancreas gland located in the upper abdomen region plays two important roles as digestive exocrine gland and hormones releasing endocrine gland. Exocrine gland composed of tiny masses called “acini” secretes enzymes for digestion. Pancreatic islets (Langerhans) as clusters or islets are responsible for important hormones secretion such as peptide hormone insulin, somatostatin, glucagon, and pancreatic polypeptide. Dysfunction in pancreatic islet leads to metabolic disorders including diabetes mellitus. The cells of pancreatic islets (α, β and δ cells) involve in the physiological and metabolic functions of insulin, correlation between immunity/insulin imbalances, cardiovascular functions. The α cells make up 20–25% of pancreatic islet cells in humans whereas β cells comprise 60–80% of islet cells in humans and mammals and δ cells comprise approximately 3–5% of islet cells. In addition, pancreas also contains polypeptide cells which are known as pancreatic polypeptide cells and these make up around 5% of pancreatic islet cells. Physiological and pathological conditions of different pancreatic hormones are also discussed in great details with suitable examples. Pancreatic progenitor or stem cells are found in rodents that β cell’s self-renewal, they form new β cells promoted by other pancreatic cells such as non β islet cells, duct cells, and acinar cells. In addition to extra pancreatic cells like neural, liver and stem or progenitor cells. In humans also, β cell neogenesis from non- β cells origin of β cell self-renewal as particularly in adulthood, restricted beta cell self-renewal happens. This chapter discusses topics related to endocrine pancreas and glucose metabolism.KeywordsEndocrine pancreasPancreatic hormonesPancreatic physiologyDiseases and glucose metabolism