[Mechanisms of the regulation of insulin secretion]

The endocrine, paracrine, and neurocrine influences of the non-glucose insulin secretion regulators on the pancreatic islets are analysed. Experiments on rats using the primary monolayer culture of isolated islet cells proved that insulin secretion is directly modulated by the growth hormone (GH), C-terminal tetrapeptide of cholecystokinin, thyroliberin, and met-enkephalin, and by certain blood plasma factors of diabetes I patients. In addition, GH is showed to stimulate the islet cell proliferation by intensifying 3H-thymidine incorporation into DNA synthesis. The blood plasma factors of IdDM patients influence the islets of Langerhans activity by either stimulating or depressing the secretory function of insulin producing cells. The aspects of functional organization of the islet cells and complex regulation of insulin secretion are discussed.