Gastric acid secretion secretin

There are a variety of peptide hormones acting in the gut the gastrins stimulate gastric acid secretion secretin and somatostatin inhibit the production of gastrins. Cholecystokinin and somatostatin can inhibit gastric acid secretion directly, and the former one causes the gall-bladder to contract and thus force bile into the duodenum. 

Secretin inhibits postprandial gastrin release (thus decreasing gastric acid secretion) and increases pancreatic exocrine secretion (e.g. of bicarbonate). The secretin receptor (like the GLP-1 receptor and vasoactive intestinal peptide (VIP) receptor) acts via Gas and cAMP elevation. A plant agonist for the secretin receptor has been isolated from the Thai anti-ulcer plant Croton sublyratus (plau-loi) (Table 5.8). 

Neuniicnsin is a 13-amino-acid peptide, nrsi Lsolaled from bovine hypothalamus, ll has now been identified in Ihc intestinal tract. The ileal muco.sa contains 90 % of the total neurotensin of ihe body. It is implicated as a releasing factor for several adenohypophyscal honnones. ll cairscs vasodilatation. increa.ses va.scular penneabilily. and increases ga.sirin secretion. It decreases. secretion of gastric acid and secretin. 

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. 

VIP has a large number of ill-defined physiological actions, some of which are shared with other similar polypeptide hormones (secretin and GIF). It acts as a neurotransmitter in the central and autonomic nervous systems and causes vasodilation and relaxation of the smooth muscles of the circulatory and genitourinary systems and the gut. Other actions of VIP include an increase of water and electrolyte secretion from the pancreas and gut release of hormones from the pancreas, gut, and hypothalamus stimulation of lipolysis, glycolysis, and bile flow and inhibition of gastrin and gastric acid secretion. Most of the actions of VIP tend to be of short duration because of its rapid degradation. 

Secretin, an intestinal hormone obtainable from the duodenum, particularly on acidification, has been used clinically as a diagnostic aid in pancreatic disease to stimulate pancreatic secretion. It has been well-established that secretin also inhibits gastric acid secretion. The most recent investigation showed that secretin Inhibited gastrin-stimulated secretion but not that induced by histamine in dogs d.th a Heidenhain pouch.Insulin reD ase by the pancreas is stimulated by secretin in dogs 9 and in man. ... 

Secretin Enteroendocrine S cells in upper small bowel 1. Stimulates pancreatic and biliary bicarbonate and water secretion 2. Regulates pancreatic enzyme secretion 3. Inhibits postprandial gastric emptying, gastrin release, and gastric acid secretion 1. Gastric acid, bile salts, fatty acids, peptides, and ethanol 2. Somatostatin inhibits secretion... 

The duodenum releases secretin, which is a hormone that suppresses gastric acid secretion. This results in the intestinal juices having a higher pH than the gastric juices in the stomach. The hormone cholecystokinin is also released. It simulates the flow of bile into the duodenum. Hormones, bile, and pancreatic enzymes tr5 sin, chymotrypsin, lipase, and amylase digest carbohydrates, protein, and fat in preparation for absorption in the small intestine. 

Wormsley KG, Grossman MI. Inhibition of gastric acid secretion by secretin and by endogenous acid in the duodenum. Gastroenterology 41 12-%, 1964. 

A complex feedback mechanism exists communicating to the stomach from the intestine. Secretin inhibits gastric acid secretion, presumably in part by stimulation of the D cell. However, it also inhibits, at least in some species, histamine-stimulated acid secretion, indicating a direct action on the parietal cell. 

A polypeptide hormone, secreted by the duodenum, which stimulates the pancreatic production of fluid rich in bicarbonate. Gastric acid stimulates secretin release. 

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. 

Gastrins stimulate the secretion of gastric acid, pepsinogen, intrinsic factor, and secretin stimulate intestinal mucosal growth increase gastric and intestinal motility... 

Experiments performed in the 1920s and already described showed that acid and food, in particular fat, in the duodenum inhibit gastric secretion. Lim and his collaborator Kosaka made an extract of the duodenal mucosa that, upon intravenous injection into a dog, inhibited food-stimulated acid secretion, and they called the active component of their extract enterogastrone. Kosaka and Lim demonstrated that their extract did not stimulate pancreatic or biliary secretion and therefore did not contain secretin or cholecystokinin. In the 1960s, when it was possible to isolate purer and more potent compounds from the duodenal mucosa, R. A, Gregory extended the definition of enterogastrone to include inhibitors released from the intestine by acid and hypertonic solutions as well as by fat. " ... 

Secretin Endocrine cells in mucosa of duodenum Acid in duodenum Inhibits gastric emptying and gastric secretion stimulates secretion of bicarbonate from pancreas stimulates secretion of bicarbonate-rich bile from liver... 

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