Endocrine cells present in different regions of the gastro-intestinal tract secrete four major peptide hormones, namely
gastrin, secretin, cholecystokinin (CCK) and gastric inhibitory peptide (GIP).
. Secretin acts on the exocrine pancreas and stimulates secretion of water and bicarbonate ions.
CCK acts on both pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice, respectively.
Gastrin is produced by the mucosal cells of the pyloric region ofthe stomach and is the most effective activator of gastric acid secretion.Two gastrins, Gastrin I and Gastrin II have been identified. Gastrin I has
17 amino acids and Gastrin II has 14 amino acids. Gastrin secretion increases with age, vagal stimulation, acetyl choline and intake of foods rich in proteins and amino acids particularly glycine. The terminal four
amino acids of gastrin are responsible for its hormonal action.
Secretin is a polypeptide with 27 amino acids of which 14 amino acids are identical to that of glucagon. It is formed in the duodenal mucosal cells. The secretion is stimulated by HCl and it increases the secretion of
electrolytes and fluid components of pancreatic juice. It is one of the factors that increase the secretion of bile by the liver. It can act like glucagon by increasing the cardiac output and lipolysis.
Cholecystokinin and Pancreozymin are two hormones that stimulate the secretion of pancreatic juice. Pancreozymin also stimulates the pancreas to secrete insulin and glucagons. Due to this action of pancreozymin, insulin secretion is higher when glucose is given orally than intravenously. Out of the 33 amino acids present in the pancreozymin, the eight C terminal amino acids are biologically active.
Cholecystokinin causes contraction of the gall bladder and discharge the bile into the duodenum. Discharge of bile is also stimulated by secretin and bile salts.
Other gut hormones
Hepatocrinin stimulates the formation of bile, which is low in bile salts. Motilin increases gastric motility. Enterogastrone and gastric inhibitory polypeptide inhibit gastric acid secretion and gastric motility. Enterocrinin stimulates the secretion of enzymes by the intestinal mucosa. Chymodenin stimulates the secretion of chymotrypsin from pancreas
gastrin, secretin, cholecystokinin (CCK) and gastric inhibitory peptide (GIP).
. Secretin acts on the exocrine pancreas and stimulates secretion of water and bicarbonate ions.
CCK acts on both pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice, respectively.
Gastrin is produced by the mucosal cells of the pyloric region ofthe stomach and is the most effective activator of gastric acid secretion.Two gastrins, Gastrin I and Gastrin II have been identified. Gastrin I has
17 amino acids and Gastrin II has 14 amino acids. Gastrin secretion increases with age, vagal stimulation, acetyl choline and intake of foods rich in proteins and amino acids particularly glycine. The terminal four
amino acids of gastrin are responsible for its hormonal action.
Secretin is a polypeptide with 27 amino acids of which 14 amino acids are identical to that of glucagon. It is formed in the duodenal mucosal cells. The secretion is stimulated by HCl and it increases the secretion of
electrolytes and fluid components of pancreatic juice. It is one of the factors that increase the secretion of bile by the liver. It can act like glucagon by increasing the cardiac output and lipolysis.
Cholecystokinin and Pancreozymin are two hormones that stimulate the secretion of pancreatic juice. Pancreozymin also stimulates the pancreas to secrete insulin and glucagons. Due to this action of pancreozymin, insulin secretion is higher when glucose is given orally than intravenously. Out of the 33 amino acids present in the pancreozymin, the eight C terminal amino acids are biologically active.
Cholecystokinin causes contraction of the gall bladder and discharge the bile into the duodenum. Discharge of bile is also stimulated by secretin and bile salts.
Other gut hormones
Hepatocrinin stimulates the formation of bile, which is low in bile salts. Motilin increases gastric motility. Enterogastrone and gastric inhibitory polypeptide inhibit gastric acid secretion and gastric motility. Enterocrinin stimulates the secretion of enzymes by the intestinal mucosa. Chymodenin stimulates the secretion of chymotrypsin from pancreas
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