Bombesin is a 14-amino acid peptide originally isolated from the skin of the European fire-bellied toad (Bombina bombina) by Vittorio Erspamer et al. and named after its source. It has two known homologs in mammals called neuromedin B and gastrin-releasing peptide. It stimulates gastrin release from G cells. It activates three different G-protein-coupled receptors known as BBR1, -2, and -3. It also activates these receptors in the brain. Together with cholecystokinin, it is the second major source of negative feedback signals that stop eating behaviour. Bombesin is also a tumor marker for small cell carcinoma of lung, gastric cancer, pancreatic cancer, and neuroblastoma.

Receptors

The anuran receptor homologue is termed. Iwabuchi et al. 2003 discovered a chicken (Gallus domesticus) receptor which is homologous to both the and fBB4 and so they named it.

Effects

Erspamer 1988 finds bombesin has a similar effect on the chicken to ranatensin, unreliably increasing or decreasing blood pressure.<ref name="Erspamer-1988-bundle">