Other · Amidated bombesin-family peptide; GRP receptor agonist
Gastrin-releasing peptide (18-27)
Also known as GRP(18-27); neuromedin C
An amidated GRP decapeptide used to investigate GRPR binding, calcium signalling and bombesin-family receptor pharmacology.
- Length
- 10 amino acids
- Half-life
- Not well characterised
- Mechanism
- The native C-terminally amidated fragment activates the gastrin-releasing peptide receptor, GRPR/BB2, principally engaging Gq/11-dependent phospholipase C signalling and intracellular calcium mobilisation. Its selectivity over other bombesin receptors depends on the receptor system and experimental conditions.
- Studied in
- Receptor-transfected cells, gastrointestinal preparations and GRPR-expressing tumour cell lines are used to examine ligand binding, calcium signalling, secretion and receptor trafficking.
About Gastrin-releasing peptide (18-27)
Gastrin-releasing peptide (18-27), also called neuromedin C, corresponds to the final ten residues of mature, 27-residue GRP. Its native sequence is GNHWAVGHLM-NH2, with a C-terminal methionine amide. GRP was originally isolated from porcine gastric tissue and recognised as a mammalian member of the bombesin peptide family. This short fragment preserves the C-terminal region responsible for much of GRP receptor recognition and activation, making its terminal chemistry particularly important.
At GRPR, also designated BB2, the fragment stimulates phospholipase C, inositol phosphate formation and calcium mobilisation. Depending on the model, downstream measurements can include ERK phosphorylation, secretory responses and receptor internalisation. Comparative experiments may include the neuromedin B receptor, BB1, and the orphan bombesin receptor subtype, BRS3/BB3. Receptor abundance, species and ligand concentration influence apparent selectivity, so a response in an uncharacterised cell line does not by itself establish GRPR involvement.
Laboratory notes
- Confirm C-terminal amidation by the supplier's identity documentation; a free-acid peptide is not chemically equivalent to native neuromedin C.
- The methionine residue can oxidise during handling; use analytical chromatography or mass spectrometry when oxidation could affect assay interpretation.
- Use receptor-negative controls and receptor-selective pharmacological controls when assigning calcium or ERK responses to GRPR.
Storage and reconstitution basics: storage guide.
Questions about Gastrin-releasing peptide (18-27)
Is GRP(18-27) the same peptide as neuromedin C?
Yes, when it has the native sequence GNHWAVGHLM and a C-terminal amide. The terminal modification should be explicitly confirmed.
How does this fragment differ from full-length GRP?
It contains only the final ten residues of the 27-residue mature peptide, while retaining the C-terminal receptor-activating region.
Does a calcium response prove selective GRPR activation?
No. Calcium mobilisation is shared by many receptors; receptor expression data, antagonist controls and appropriate comparison cell lines are needed.
Is Gastrin-releasing peptide (18-27) for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.