Secretin
From Free net encyclopedia
Secretin is a peptide hormone produced in the S cells of the duodenum. It is secreted in response to low duodenal pH, and stimulates the secretion of bicarbonate from the liver, pancreas, and duodenal Brunner's glands. It also reduces acid secretion from the stomach by inhibiting gastrin release from G cells. This helps neutralize the pH of the digestive products entering the duodenum from the stomach, as enzymes from the pancreas (eg, pancreatic amylase and pancreatic lipase) function optimally at neutral pH.
Structure
Secretin is a 27-amino acid peptide hormone homologous to glucagon.
History
Secretin was the first substance which was identified to cause a physiological effect in the body after being transported via the blood. The term hormone was coined by Bayliss and Starling to categorise such chemical messengers.