QS Study

Secretin is a hormone produced by the digestive tract. It influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver. It stimulates the release of bicarbonate and water from the pancreas to aid digestion. It has an enormous impact on the fluid balance and levels of other digestive hormones while also benefit the heart, brain, and lungs.

Source – S cells of duodenum and jejunum. It’s released by the duodenum, the upper part of the small intestine.

Cause of secretion – Presence of acidic Chyme into the duodenum.

The site of action: Pancreas and Stomach.


  • Stimulates hydro-lytic type of pancreatic secretion (HCO3 – rich secretion)
  • Inhibits gastrin secretion, So it decreases gastric HCl and pepsinogen secretion.
  • Contraction of the pyloric sphincter.
  • It helps digestion by causing the stomach to make pepsin, prompting the liver to make bile, and causing the pancreas to make digestive juices.