Glucagon

Secretion of Insulin in Response to Diet and Hormones

“…Glucagon is formed within pancreatic  islet cells and has a hyperglycemic affect on the body (5). It stimulates glucose production from amino acids and glycerol through gluconeogenesis and from the liver through glycogenolysis.…”

Intermediate Filament Keratins in The Exocrine Pancreas

“…By contrast, in intestinal enteroendocrine cells proglucagon is processed to GLP-1, GLP-2, oxyntomodulin, and glicentin (171). The major role of glucagon is to antagonize the effects of insulin and maintain plasma glucose homeostasis by promoting hepatic gluconeogenesis and glycogenolysis and inhibiting glycogen synthesis (25). The major regulators of glucagon secretion by islet alpha cells are glucose which inhibits and amino acids as well as parasympathetic and sympathetic nerves which stimulate glucagon release.…”

“…The mechanism of this inhibition is unclear in these studies. In vitro, studies have been carried out in the perfused pancreas, pancreatic segments and lobules with mixed results (25). With the development of isolated pancreatic acini and acinar cells, natural purified glucagon was shown to stimulate amylase secretion and increase cyclic AMP in rat, mouse and guinea pig acini (237,278,279).…”

Secretion of Insulin in Response to Diet and Hormones

“…As the second most abundant islet cell type, they make up about 35% of islet mass in humans (6). Glucagon's primary function is to prevent hypoglycemia by stimulating glycogenolysis and hepatic neoglucogenesis (5). Somatostatin-producing  cells comprise less than 10% of islet mass, and are evenly distributed throughout the pancreas (1).…”