Understand the source comparison
VIP vs Related Peptides: PACAP, Secretin, and Glucagon Family
VIP (Vasoactive Intestinal Peptide) 28 VPAC1, VPAC2 Immune modulation, circadian synchronization, smooth muscle relaxation 1–2 minutes Autoimmune disease, neuroinflammation, circadian disorders PACAP (Pituitary Adenylate Cyclase-Activating Polypeptide) 27 or 3
No winner is assigned.
This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- VIP (Vasoactive Intestinal Peptide)
- 28
- VPAC1, VPAC2
- Immune modulation, circadian synchronization, smooth muscle relaxation
- 1–2 minutes
- Autoimmune disease, neuroinflammation, circadian disorders
- PACAP (Pituitary Adenylate Cyclase-Activating Polypeptide)
- 27 or 38
- PAC1, VPAC1, VPAC2
- Neuroprotection, stress response, neuroendocrine regulation
- 5–10 minutes
- Traumatic brain injury, PTSD, neurodegenerative disease
- Secretin
- 27
- Secretin receptor
- Pancreatic bicarbonate secretion, gastric acid neutralization
- 2–3 minutes
- Pancreatic function testing, gastroesophageal disorders
- Glucagon
- 29
- Glucagon receptor
- Hepatic glucose output, glycogenolysis activation
- 3–6 minutes
- Diabetes, hypoglycemia rescue, metabolic studies
- VIP shares structural homology with PACAP, secretin, and glucagon. All members of the secretin/glucagon superfamily. PACAP (Pituitary Adenylate Cyclase-Activating Polypeptide) is the closest relative, differing by only one amino acid in its 27-residue form. Both peptides bind VPAC1 and VPAC2, but PACAP also binds PAC1 receptors with 1000-fold higher affinity than VIP, making it a more potent neuroprotective agent. The functional distinction: VIP dominates in immune and circadian contexts, while PACAP specializes in acute stress response and synaptic plasticity.
- Secretin, by contrast, has no direct immune function. It regulates pancreatic and biliary secretions exclusively through the secretin receptor. Glucagon acts on hepatic glucose metabolism through the glucagon receptor. These peptides share a common evolutionary origin but have diverged into distinct physiological niches. VIP is unique among them for its dual role as both a neurotransmitter and a systemic hormone with broad immunomodulatory capacity.