Secretin

Secretin is a linear 27-aa peptide that was initially discovered from the porcine intestine based on its activities in stimulating pancreatic juice. The primary structure of secretin is highly conserved among mammalian species, but the sequence identity in nonmammalian species up to avians is lower, and secretin-like sequences have not been found in teleost and lungfish genomes. The secretin receptor is a member of the G protein-coupled receptors, with seven conserved transmembrane domains. Secretin and its receptor are widely expressed in multiple tissues. In peripheral tissue, secretin regulates the pancreatic exocrine secretion of bicarbonate, water, and electrolytes as well as gastric acid secretion. In the brain, secretin regulates social interaction, water and food intake, motor coordination, and spatial and motor learning behaviors. Sct knockout mice have impaired spatial learning ability in adults, and Sctr knockout mice have impaired renal function.