Secretin

Secretin is a hormone secreted by S-cells of the upper part of the small intestine.

The stimulus for release of secretin are the products of protein digestion and the acidic environment that wets the mucosa of the upper part of the small intestine. Fatty acids in chyme also play a role in stimulation.

The main effect of secretin is the stimulation of pancreatic secretion, mainly pancreatic ducts. It increases the secretion of HCO3-, water and ions, and thus the secretion of aqueous alkaline pancreatic juice. It decreases gastric acid secretion and may cause contraction of the pyloric sphincter. It suppresses the movements of the colon.

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