Gastrointestinal Hormones

Name of Hormones       Source of secretion Functions (Actions)
1.       Gastrin






G-cells in stomach

TG cells in GI tract

Islets in fetal pancreas

Anterior pituitary



Stimulates gastric secretion and motility.

Promotes growth of gastric mucosa.

Stimulates release of pancreatic hormones.

Stimulates secretion of pancreatic juice.

Stimulates secretion of pancreatic hormones.


2.       Secretin



S cells of small intestine




Stimulates secretion of watery and alkaline pancreatic secretion.

Inhibits gastric secretion and motility.

Constricts pyloric sphincter.

Increases potency of cholecystokinin action.

3.       Cholecystokinin   I cells of small intestine Contracts gallbladder.

Stimulates pancreatic secretion with enzymes.

Accelerates secretin activity.

Increases enterokinase secretion.

Inhibits gastric motility.

Increases intestinal motility.

Augments contraction of pyloric sphincter.

Suppresses hunger.

Induces drug tolerance to opioids.

4.       Gastric inhibitory peptide (GIP)


K cells in duodenum and jejunum

Antrum of stomach

Stimulates insulin secretion

Inhibits gastric secretion.

5.       Vasoactive intestinal polypeptide (VIP) Stomach

Small and large intestine

Dilates splanchnic blood vessels.

Inhibits HCL secretion in gastric juice.

Stimulates secretion of succus entericus.

Relaxes smooth muscles of intestine.

Augments acetylcholine action on salivary glands.

Stimulates insulin secretion.

6.       Glucagon Alpha cells in pancreas

A cells in stomach

L cells in intestine

Increases blood sugar level.


7.       Glicentin L cells in duodenum and jejunum Increases blood sugar level.
8.       Glucagon like polypeptide-1 (GLP-1) Alpha cells in pancreas


Stimulates insulin secretion.

Inhibits gastric motility.

9.       GLP-2 L cells in ileum and colon Suppresses appetite.
10.   Somatostatin Hypothalamus

D cells in pancreas

D cells in stomach and small intestine

Inhibits secretion of growth hormone.

Inhibits gastric secretion and motility.

Inhibits secretion of pancreatic juice.

Inhibits secretion of GI hormones.

11.   Pancreatic polypeptide PP cells in pancreas

Small intestine

Increases secretion of glucagons.

Decreases pancreatic secretion.

12.   Peptide YY L cells of ileum and colon Inhibits gastric secretion and motility

Reduces secretion of pancreatic juice.

Inhibits intestinal motility and bowel passage.

Suppresses appetite and food intake.

13.   Neuropeptide Y Ileum and colon

Brain and ANS

Increases blood flow in enteric blood vessels
14.   Motilin Mo cells in stomach and intestine

Entero-chromoffin cells in intestine

Accelerates gastric emptying.

Increases movements of small intestine.

Increases peristalsis in colon

15.   Substance P Brain

Small intestine

Increases movements of small intestine.


16.   Ghrelin Stomach





Promotes growth hormones (GH) release.

Induces appetite and food intake.

Stimulates gastric emptying.


Different Gastrointestinal hormones and their Action - Online Science Notes

                                                                               Image source: onlinescience






Gastrointestinal Hormones