Gut & appetite
The gut's hormonal report on digestion, satiety, and motility.
PYY · CCK · secretin · motilin
Overview
The gut is the body's largest endocrine organ. Enteroendocrine cells lining the GI tract release peptides in response to nutrients, coordinating digestion, motility, and the satiety signals that reach the brain.
PYY and (from the same L-cells) GLP-1 are released after meals and promote satiety; CCK triggers gallbladder contraction and pancreatic enzyme release; secretin regulates bicarbonate; motilin paces the migrating motor complex between meals.
Because several of these peptides converge on appetite and gastric emptying, the gut–brain axis is central to understanding both normal satiety and metabolic pharmacology.
Key signals
Reference notes
- L-cells co-secrete GLP-1 and PYY, linking this family directly to the incretin/metabolic axis.
- Satiety is multi-signal: no single gut peptide is the 'fullness hormone' — they act in concert.
- Motilin's between-meal role is distinct from the post-meal satiety peptides — timing is the differentiator.