Multiple gut-derived peptide signals (CCK, GLP-1, PYY, ghrelin, oxyntomodulin) control meal-to-meal satiety while long-term fat signals (leptin, insulin) regulate body weight — an integrated two-tier system.
Two-tier systemMeal-by-meal gut signals + long-term fat signals = the complete appetite control architecture that modern obesity drugs target
What the researchers found
Satiety is controlled by a two-tier peripheral signaling system: short-term gut peptides (CCK, GLP-1, PYY, ghrelin, oxyntomodulin) for meal control and long-term adiposity signals (leptin, insulin) for body weight regulation, integrated by brainstem and hypothalamic circuits.
Why it matters
This review describes the complete signaling architecture that modern obesity drugs target. GLP-1 agonists (semaglutide) work through one of the many pathways described here.
How the study worked
Comprehensive review of all peripheral satiety and hunger signals, their receptors, neural pathways, and integration in central appetite circuits.
What this study cannot tell us
Review from 2003. Some signals described were still being characterized. The relative importance of each signal for human obesity treatment was debated.
How to read the evidence
Strong evidence from a comprehensive review synthesizing decades of appetite physiology research.
When this study was published
Published in 2003. This framework has been validated by the clinical success of GLP-1 agonists (semaglutide) and combined GLP-1/GIP drugs (tirzepatide).
The bigger picture
Understanding the full appetite signaling network reveals why single-target drugs have limited weight loss. The most effective future treatments may combine signals from multiple tiers.
Questions still open
- Can multi-signal targeting achieve greater weight loss than GLP-1 alone?
- Which combination of gut peptide mimetics would be most effective?
- Does chronic obesity alter the sensitivity of these signaling pathways?
Common questions
Why is appetite so complex?
How do current obesity drugs fit in?
Read the original research
Peripheral signals in the control of satiety and hunger.
Current opinion in clinical nutrition and metabolic care, 6(6), 621-9
Citation
Drazen, Deborah L; Woods, Stephen C. (2003). Peripheral signals in the control of satiety and hunger.. Current opinion in clinical nutrition and metabolic care, 6(6), 621-9.