In mammals, the gastrointestinal peptide hormone, secretin is a 27-amino acid peptide that was first studied in 1902 by Bayliss and Starling from the extracts of the jejunal mucosa for its ability to stimulate pancreatic secretion. In human, 10 members exist and sequence and functional homologues and ligand-receptor pairs have been characterised in representatives of most vertebrate classes. Secretin-like family GPCR homologues have also been isolated in non-vertebrate genomes however their corresponding ligands have not been convincingly identified and their evolution remains enigmatic. The physiological roles of secretin and its receptor is as follows.
(1)Secretin is a member of the secretin-glucagon family and is secreted by S cells of the duodenum in the crypts of Lieberkühn.
(2) Secretin affects the function of a number of organ systems and cell types.
(3) Secretin exerts its biological effects through G-protein coupled secretin receptors (SR), which are expressed in the basolateral domain of several cells. In addition to regulating the pH of the duodenal content by the control of gastric acid secretion, secretin regulates the secretion of bicarbonate ions into the duodenum from the epithelia lining the pancreatic and biliary ducts. In addition to regulating water homeostasis.
(4) secretin has been considered as a neuropeptide hormone since it is also expressed in the central nervous system (CNS).
Recent evidence has indicated that secretin has pleiotropic effects in several organ systems (including the biliary epithelium) and has been termed a neuroendocrine hormone.
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 Zhang L, Chow BK. The central mechanisms of secretin in regulating multiple behaviors. Front Endocrinol (Lausanne). 2014, 21(5):77  João CR Cardoso, Florbela A Vieira, Ana S Gomes. The serendipitous origin of chordate secretin peptide family members. BMC Evol Biol. 2010,10: 135.  Afroze S, Meng F, Jensen K. The physiological roles of secretin and its receptor. Ann Transl Med. 2013,1(3):29