Bombesin

Summary

Bombesin is a 14-amino acid neuropeptide originally isolated from the skin of the European fire-bellied toad (Bombina bombina). It is the amphibian homolog of mammalian gastrin-releasing peptide (GRP). Widely used as a research tool to study appetite regulation, oncology (overexpressed bombesin receptors in certain cancers), and as a targeting ligand for nuclear medicine imaging and drug delivery in prostate and breast cancers.

Mechanism of Action

Binds to bombesin receptors (BB1/NMBR, BB2/GRPR, BB3/BRS-3), acting as an agonist to stimulate gastrin, cholecystokinin, and other GI hormone release; promotes smooth muscle contraction, exocrine pancreatic secretion, and thermoregulation; activates phospholipase C via Gq-coupled signaling.

Routes of Administration

Goals & Uses

• Appetite suppression / satiety signaling researchMetabolic / NeuroscienceModerate
• Targeted drug delivery vehicleOncology / Drug DeliveryLow
• Cancer receptor imaging (prostate, breast, SCLC)Oncology / Nuclear MedicineModerate
• Thermoregulation researchNeuroscienceLow
• GI hormone secretion stimulationGastroenterologyModerate

Contraindications

• Severe peptic ulcer diseaseGastroenterologyModerate
• Active GI obstruction or ileusGastroenterologyModerate
• Hypersensitivity to bombesin or related peptidesAllergy / ImmunologyHigh

Adverse Effects

• AnaphylaxisImmunologicRareSevere life-threatening allergic reaction
• Injection site reactionsLocalCommon
• HypotensionCardiovascularUncommonLow blood pressure
• FlushingVascularUncommonWarmth and redness of the skin
• Nausea and vomitingGastrointestinalCommon
• Abdominal crampingGastrointestinalCommon

Drug Interactions

• AnticholinergicsLow
• Proton pump inhibitors / H2 blockersLow

Population Constraints

• PregnancyReproductive SafetyRelative
• Pediatric populationsAgeRelative
• Renal or hepatic impairmentOrgan DysfunctionRelative

Regulatory Status

• European UnionInvestigationalUsed in investigational nuclear medicine studies (e.g., radiolabeled analogs); no EMA marketing authorization.
• United StatesUnapprovedNot FDA-approved for any therapeutic indication; used as research reagent and in investigational radiolabeled imaging protocols (IND required).
• United KingdomUnknownNo MHRA approval; may be used under research or clinical trial exemptions.

Not approved for therapeutic use by FDA, EMA, or MHRA. Used primarily as a research reagent and as a targeting vector in experimental radiolabeled imaging agents (e.g., 99mTc-bombesin analogs) under investigational protocols.

Evidence & Sources

No sources recorded yet.