Gastrin-releasing peptide

The hastrin-releasing peptide (GRP) was isolated from the porcine stomach, and was believed to be the mammalian counterpart of the amphibian peptide bombesin-itself originally isolated from the porcine stomach and subsequently in other vertebrates. A large body of research indicates that GRP is distributed widely in the central nervous system of mammals in addition to the gastrointestinal tract. In mammals, bombesin-like peptides act through a family of at least three GPCRs, namely the GRP-preferring receptor (GRPR), the neuromedin B-preferring receptor (NMBR), and the bombesin receptor subtype-3 (BRS-3), which is considered an orphan receptor. To date, it has been reported that GRP plays significant roles in many physiological processes, including food intake, circadian rhythms, male sexual behavior, sigh control, and fear memory consolidation, through the specific GRPR-mediated mechanisms.