PeptideHormone

Secretin

Stimulates pancreatic bicarbonate to neutralize gastric acid.

EndogenousEstablished

Identity

Class
Secretin-family peptide (27 aa)
Source
Duodenal S-cells
Receptor
Secretin receptor (a class B GPCR)

Key properties

Molecular weight
~3,039.5 Da
Half-life (native)
~4 min
Model dosing

Approximate values for the native hormone. Engineered analogs are often deliberately larger and far longer-acting.

Mechanism

When acidic chyme enters the duodenum, S-cells release secretin, which stimulates the pancreas and bile ducts to secrete bicarbonate-rich fluid, neutralizing acid to protect the mucosa and create the pH range digestive enzymes need.

Reference notes

  • Secretin was the first hormone ever discovered, giving the field its name.
  • Its trigger is duodenal acidity — a direct chemical feedback loop.
  • It is the prototype of the secretin/glucagon peptide superfamily.

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

  1. 1.Secretin, 100 years later · Journal of gastroenterology, 2003 · PMID 14673718
  2. 2.Secretin: a hormone for HCO(3)(-) homeostasis · Pflugers Archiv : European journal of physiology, 2024 · PMID 38221598