VIP

VIP Research Standard

Vasoactive intestinal peptide (CAS 37221-79-7) is a 28-residue peptide supplied as a 10 mg lyophilized powder in a 3 mL vial. It is an endogenous ligand at two class B GPCRs, VPAC1 and VPAC2, which it binds with comparable affinity but activates very differently — a dissociation that makes it a useful reference for receptor-subtype work.^[1]

Mechanism of Action & Research Context

The molecular targets are VPAC1 and VPAC2, shared with pituitary adenylate cyclase activating polypeptide (PACAP), which additionally binds PAC1.^[2]

• Equal binding, unequal activation. VIP binds VPAC1-expressing HT-29 membranes and VPAC2-expressing Molt-4b membranes with near-identical high affinity (K_D 1.6 ± 0.2 and 1.7 ± 0.9 nM). But functionally it is a potent VPAC1 agonist, driving a 200-fold cAMP increase, and only a weak VPAC2 agonist at 14-fold. Affinity and efficacy come apart here, which is exactly the kind of distinction a binding assay alone would miss.^[1]

• A natural fragment inverts the profile. VIP4-28, generated by human lymphocytes, binds both receptors with the same high affinity, acts as an even stronger VPAC1 agonist (400-fold cAMP increase), and is a potent VPAC2 antagonist — inhibiting VPAC2-mediated cAMP by up to 95% with no antagonism at VPAC1. Proteolytic processing of the parent peptide therefore produces a subtype-selective tool.^[1]

• Cell lines that express one receptor each. HT-29 (VPAC1 only) and Molt-4b (VPAC2 only) were identified by real-time RT-PCR, which is what makes clean subtype comparison possible.^[1]

• Downstream signalling extends beyond cAMP. The VIP/PACAP receptor cascades include transactivation of the epidermal growth factor receptor family, and the three receptor subtypes are overexpressed in several tissue types — which is why receptor distribution is measured alongside signalling.^[2]

Research Applications

Primary fields of in vitro laboratory investigation include:

• Receptor subtype binding and cAMP assays in single-subtype cell lines.^[1]

• Affinity-versus-efficacy dissociation studies, using VIP as the reference where the two diverge.^[1]

• Fragment and proteolysis work, comparing VIP against VIP4-28 and related fragments.^[1]

• Receptor expression profiling by real-time RT-PCR.^[1,2]

• Growth factor receptor transactivation studies.^[2]

Analytical Documentation

Purity and identity vary by manufacturing lot. Kimera Chems does not publish a single fixed purity figure for this item; refer to the batch-specific Certificate of Analysis (COA) issued for the lot received, which reflects third-party analytical testing for that lot.

References

1. Summers MA, O'Dorisio MS, Cox MO, Lara-Marquez M, Goetzl EJ. A lymphocyte-generated fragment of vasoactive intestinal peptide with VPAC1 agonist activity and VPAC2 antagonist effects. J Pharmacol Exp Ther. 2003;306(2):638–645. doi:10.1124/jpet.103.050583
2. Moody TW, Nuche-Berenguer B, Jensen RT. Vasoactive intestinal peptide/pituitary adenylate cyclase activating polypeptide, and their receptors and cancer. Curr Opin Endocrinol Diabetes Obes. 2016;23(1):38–47. doi:10.1097/MED.0000000000000218

Storage & Handling

Store at controlled room temperature, sealed and protected from light.

Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.

Related Research Compounds

• Thymosin Alpha-1
• Larazotide
• Arimistane
• Enclomiphene

Research Use Only Disclaimer: This product is labeled and sold "For Research Use Only - NOT FOR HUMAN CONSUMPTION." It is not a drug, dietary supplement, food, cosmetic, or medical device, and it is not approved by the FDA or any other regulator for human or veterinary use. It is supplied to approved account holders as a research chemical for laboratory use and must be handled in accordance with applicable law.