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Metabolic & GLP-1 · Reference monograph

Duodenal hormone used in diagnostic testing

Reference compound — not available from Purity Peptides. Shown for research context.

Overview

Secretin is a 27-amino-acid peptide hormone released by S-cells of the duodenal mucosa when acidic chyme enters the small intestine. Its discovery in 1902 by William Bayliss and Ernest Starling at University College London is a landmark in physiology: by showing that a chemical messenger carried in the blood could stimulate pancreatic secretion without nerve involvement, they established the concept of hormonal signalling, and Starling introduced the word hormone in 1905.

Secretin was the founding member of the secretin/glucagon peptide family, which also includes VIP, PACAP, GLP-1, incretin hormone from intestinal K cells; its receptor is a target of dual and triple agonists.">GIP and glucagon, and its receptor gives its name to the class B, or secretin-family, G protein-coupled receptors. Synthetic human secretin is an approved prescription product for diagnostic purposes, including assessment of pancreatic exocrine function, aiding the diagnosis of gastrinoma and improving visualisation of pancreatic ducts during magnetic resonance cholangiopancreatography. In research, secretin is used to study pancreatic ductal physiology, bicarbonate transport, receptor pharmacology and central functions of the peptide.

Mechanism studied

  1. Duodenal S-cells
  2. Secretin
  3. Pancreatic bicarbonate
  4. Diagnostic readout

Secretin binds the secretin receptor, a class B G protein-coupled receptor expressed on pancreatic ductal cells, cholangiocytes, gastric cells and in parts of the brain. Receptor activation couples to Gs, increasing cAMP and activating protein kinase A, which phosphorylates and opens the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Coupled with chloride-bicarbonate exchangers, this produces a large volume of bicarbonate-rich fluid that neutralises gastric acid in the duodenum. Secretin also inhibits gastric acid secretion and gastrin release. In gastrinoma cells, which aberrantly express secretin receptors, secretin paradoxically stimulates gastrin release, the basis of the diagnostic stimulation test.

Research highlights

  • 01Discovered in 1902 by Bayliss and Starling, the first substance recognised as a hormone.
  • 02Its receptor was the first cloned member of the class B, or secretin-family, G protein-coupled receptors.
  • 03Diagnostic applications include pancreatic function testing, gastrinoma provocation testing and secretin-enhanced MRCP.
  • 04Anecdotal reports in the 1990s prompted controlled trials in autism that did not show an effect, a frequently cited example of evidence evaluation.
  • 05Open questions include secretin's roles in the brain, including water homeostasis and neural development in rodent models.

Latest published research

7,353 papers on PubMed →

  1. A generalizable method for the purification and biophysical characterization of bacterial membrane receptors

    Bosetto F et al. · Protein science : a publication of the Protein Society · 2026 Nov · PMID 42876396

  2. Structural and functional insights into rhodopsin-like and secretin-like GPCR-arrestin interactions and regulation

    Gupta V et al. · The FEBS journal · 2026 Oct 27 · PMID 42936877

  3. Endoscopic ultrasound in the diagnosis of chronic pancreatitis: a structured state-of-the-art review

    Iglesias-García J et al. · Revista espanola de enfermedades digestivas · 2026 Oct 26 · PMID 42929253

  4. Evaluation of Pirfenidone for Recurrent Acute Pancreatitis: Protocol for a Randomized Trial

    Jain T et al. · The Journal of surgical research · 2026 Oct 22 · PMID 42913268

  5. Beyond Digestion: Secretin as a Key Regulator of Systemic pH

    Andersen JF et al. · Annual review of physiology · 2026 Oct 16 · PMID 42887002

  6. Extensive polycystic pancreas in a child: A rare congenital lesion

    De Grande B et al. · Journal of pediatric gastroenterology and nutrition · 2026 Oct 13 · PMID 42865194

  7. Osteopathic manipulative treatment as an adjunct therapy in a pediatric patient with chronic pancreatitis and visceral hyperalgesia: a case report

    Levy A et al. · Frontiers in medicine · 2026 · PMID 42920523

  8. Intestinal FXR agonism synergizes with leptin to improve obesity by reducing appetite via secretin

    Zhu X et al. · EMBO reports · 2026 Oct 5 · PMID 42834123

Live feed from PubMed (NCBI) for “Secretin”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

53 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “Secretin”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]Manufacturer's prescribing information — FDA / EMA / ANVISA
  2. [2]PubMed — reviews on secretin and pancreatic function tests

FAQ

  • Secretin was the first hormone identified. Bayliss and Starling's 1902 experiments showed that duodenal extracts could trigger pancreatic secretion through the bloodstream rather than nerves, establishing endocrinology as a discipline and introducing the concept of chemical messengers.

  • Synthetic human secretin is approved to stimulate pancreatic secretion for assessing exocrine function, to aid gastrinoma diagnosis through a paradoxical gastrin response, and to enhance pancreatic duct visualisation during MRCP. Each application relies on secretin's predictable effect on pancreatic or tumour cells.

  • The secretin family groups structurally related hormones and neuropeptides including secretin, glucagon, GLP-1, GLP-2, GIP, VIP, PACAP and growth hormone-releasing hormone. They act on related class B G protein-coupled receptors that share a large extracellular N-terminal domain.

FOR RESEARCH USE ONLY.Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.

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