Gastrin-producing cells

Gastrin-Producing Cells Secrete gastrin, a hormone that regulates the release of enzymes during digestion... 

Gastrin-producing cells are not evident in the adult pancreas, yet gastrinomas were previously considered to be predominantly pancreatic endocrine tumors. Currently, it is apparent that at least 50% of the lesions occur in the duodenum. In much the same fashion as carcinoid tumors, the majority of lesions are metastatic or multiple at diagnosis. 

Pancreas a vertebrate organ producing a digestive secretion which enters the adjacent duodenum in response to the hormones Secretin (see) and Cholecys-tokinin (see). It also contains about 1 million islets of Langerhans, each with a diameter of ISO un these have a rich blood supply and are innervated with unmyelinated nerve fibers. The islets contain various types of hormone-producing cells, the A cells which produce Glucagon (see), the B cells which make Insulin (see) and the D cells which manufacture Gastrin (see). 

Vassallo G, Solcia E, Bussolati G, et al. Non-G cell gastrin-producing tumours on the pancreas. Virchows Arch B 11 66-79, 1971. 

Gastrin is a hormone produced by gastric endocrine tissue — specifically, the G cells in the pyloric gland area. It is released into the blood and carried back to the stomach. The major function of gastrin is to enhance acid secretion by directly stimulating parietal cells (HC1) and chief cells (pepsinogen). Gastrin also stimulates the local release of histamine from enterochromaf-fin-like cells in the wall of the stomach. Histamine stimulates parietal cells to release HC1. 

Gastrin inhibition. Hydrogenated oil, administered to adult rats, produced a significant reduction in antral and plasma gastrin concentrations . Gastrointestinal effect. Oil, administered to rats, induced the secretion of surfactantlike particles in the small intestine ". Genotoxic activity. Coconut oil acid diethanolamine condensate with or without S9 activation enzyme, in cell culture, pro-... 

In addition to HC1, the parietal cells produce intrinsic factor, which binds to dietary Bi2 and facilitates its absorption in the ileum. Gastrin, a hormone which promotes secretory activity in the stomach, is also produced by the gastric mucosal cells and released into the blood. 

Gastric acid production is regulated by both the autonomic nervous system and several hormones. The parasympathetic nervous system, via the vagus nerve and the hormone gastrin, stimulates the parietal cell to produce gastric acid, acting both directly on parietal cells and indirectly through the stimulation of the secretion of the hormone histamine from ECL cells. Vasoactive intestinal peptides, cholecystokinin and secretin all inhibit acid production. 

Secretin is a 27-residue peptide amide hormone produced by S cells of the duodenum. The primary effect of secretin is stimulating the release of bicarbonate from liver, pancreas, and duodenal tissues to inhibit gastrin-induced gastric acid release. It also enhances the effects of cholecystokinin and promotes normal growth and maintenance of the pancreas. 

The cephalic phase of digestion stimulates only a fraction of the maximum possible levels of gastric and pancreatic secretions. This phase does not seem to produce a rise in the levels of gastrin and CCK. Cephalic stimulation of the pancreas, as mediated by the vagus nerve, provokes release of pancreatic enzymes into the small intestine. Cephalic stimulation of the parietal cells, as mediated by the vagus nerve, provokes release of gastric acid into the lumen of the stomach- In humans, the cephalic phase does not seem to result in release of bicarbonate into the lumen of the small intestine. 

Gastric acid secretion can be inhibited by several mechanisms including acid in the stomach (pH 3 inhibits gastrin release), acid in the duodenum, the presence of fat in the pancreas, and hypertonic fluids or hyperglycemia. Somatostatin, a hormone produced by antral mucosal endocrine cells (D cells), inhibits the release of gastrin by directly inhibiting the parietal cells. Somatostatin is also present in other GI tissue and the pancreas. C cells, endocrine cells in the proximal small intestine, secrete secretin in response to mucosal acidification, which also decreases gastric secretion. 

---