Secretin
Overview
A 27-amino acid peptide hormone produced by S-cells of the duodenal and jejunal mucosa in response to acidic chyme entering the small intestine. Secretin stimulates pancreatic ductal cells to secrete bicarbonate-rich fluid, neutralizing duodenal acid, and promotes bile flow from hepatocytes. It was the first hormone ever identified (Bayliss and Starling, 1902) and serves as a key diagnostic tool in gastroenterology and endocrinology.
Key Research Findings
FDA-approved as a diagnostic agent for pancreatic exocrine function (secretin stimulation test), gastrinoma/Zollinger-Ellison syndrome diagnosis (paradoxical gastrin rise), and to facilitate MRCP imaging of pancreatic ducts. Synthetic human secretin (ChiRhoStim/SecreFlo) replaced porcine-derived products. Investigated but not proven effective as a treatment for autism spectrum disorder despite initial case reports.
Intravenous
FDA Approved
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Find a Secretin ProviderRelated Peptides
Octreotide (Sandostatin)
FDA ApprovedA synthetic octapeptide analog of somatostatin with a substantially longer half-life (90 minutes IV, 6 hours subcutaneous vs. 2 minutes for native somatostatin). Octreotide binds somatostatin receptors (primarily SSTR2 and SSTR5) to inhibit the secretion of GH, glucagon, insulin, gastrin, secretin, VIP, and other GI hormones. It reduces splanchnic blood flow, GI motility, and exocrine pancreatic secretion.
Lanreotide (Somatuline Depot)
FDA ApprovedA synthetic octapeptide analog of somatostatin with high affinity for SSTR2 and moderate affinity for SSTR5 receptors. Lanreotide is formulated as a supersaturated solution that forms a drug depot at the injection site, providing sustained release over 4 weeks. It inhibits GH secretion, GI hormone release, and has direct antiproliferative effects on neuroendocrine tumor cells through cell cycle arrest and apoptosis induction.
Pasireotide (Signifor)
FDA ApprovedA multireceptor-targeted somatostatin analog with high binding affinity for SSTR1, SSTR2, SSTR3, and SSTR5, particularly notable for its 40-fold greater affinity for SSTR5 compared to octreotide. This receptor profile makes pasireotide uniquely effective in Cushing's disease, where corticotroph adenomas predominantly express SSTR5. Pasireotide suppresses ACTH secretion from pituitary corticotroph tumors, reducing cortisol production.
Plecanatide (Trulance)
FDA ApprovedA synthetic 16-amino acid peptide structurally related to uroguanylin, an endogenous intestinal peptide that regulates fluid and electrolyte homeostasis in the GI tract. Plecanatide activates guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells in a pH-dependent manner, preferentially in the proximal small intestine where pH is slightly acidic. GC-C activation increases intracellular and extracellular cGMP, stimulating chloride and bicarbonate secretion while reducing visceral pain signaling.