Lecture notes on Gastro intestinal hormones

Hormones are metabolic regulators .They generally regulate metabolism  by  regulating  the secretion of a particular enzymes involved in a particular metabolism. Digestion is a type of   metabolism (catabolism) which is regulated by a series of enzymes .The secretion of all  enzymes involved in the process of digestion and absorption  are regulated  by many hormones and  are as follows.

1.Gastrin :This hormone is secreted from the mucosa of pyloric stomach. The entry of food into the  stomach stimulate its secretion. In stomach it stimulates the secretion of gastric juice and also cause the  constriction of cardiac sphincter.

2.Enterogastrone : This is  secreted  from the duodenal epithelium and its secretion is stimulated when the chyme enter into the  duodenum. In stomach it inhibits secretion of gastric juice and also slows gastric contractions  and thereby delay its emptying.

3.Secretin: This is secreted from the duodenal epithelium  and its secretion is stimulated when the acidic chyme enter into the duodenum. It mainly affect the pancreas, liver and the  stomach. In pancreas it stimulates the release of sodium bicarbonate in the pancreatic juice. In liver it stimulates the secretion of bile and in stomach it inhibit the secretion gastrin.

4.Cholecystokinin-panreozymin: This is secreted from the duodenal epithelium and its secretion is stimulated by the presence of fats in duodenum. It  mainly  acts on pancreas and gall bladder. In pancreas it stimulates the secretion of pancreatic juice and in gall bladder it stimulates the release of gall or bile.

5.Villikinin: This is secreted from the intestinal epithelium and its secretion is stimulated by  the food in small intestine. In intestine it accelerates the movement of  villi.

6.Duocrinin:This hormone is secreted from the  intestinal epithelium  and its secretion is stimulated by the acidic chyme in the intestine. In intestine it stimulates the secretion of mucus from the Brunner ^,s gland.

7.Enterocrinin:This is secreted from the intestinal epithelium and its secretion is stimulated by the acid chyme in the intestine. In intestine it stimulates the release of enzymes by the Leiberkuhn crypts.