The bombesin receptor family is a member of the G protein-coupled receptor superfamily and consists of three subtypes of receptors: BB1 (neuromedin B receptor), BB2 (gastrin-releasing peptide receptor), and BB3. These receptors are widely distributed in mammals especially in the CNS and gastrointestinal tract and have numerous effects both physiologically and in pathologic processes including having an autocrine growth action on normal tissues and tumors; potent CNS effects (satiety, circadian rhythm, various behaviors); and potent effects in the immune, gastrointestinal, respiratory and urogenital systems. The human BB2 receptor has a greater than 50-fold higher affinity for gastrin-releasing peptide than neuromedin B. Interaction of ligand and BB2 activates the Gαq/11 pathway and increase the intracellular calcium concentration. GenScript’s BB2-expressing stable cell line was made in CHO-K1 host cell and optimized for calcium assays.