Pituitary adenylate cyclase-activating polypeptide-related peptide

PRP, also named GHRH-like peptide, was identified as a structurally related peptide of PACAP on the PACAP precursor. PRP and PRP-like peptides were identified in vertebrates and tunicates, respectively. Mammalian PRP peptides are 29 aa residues in length, nonmammalian PRP peptides 43-46 aa, and tunicate PRP-like peptides 27 aa residues. The PRP/PACAP precursor is detected most abundantly in the central nervous tissues, especially in the hypothalamus. The PRP receptor, formerly referred to as the GHRH receptor, is a GPCR with seven transmembrane helical domains. Although highly specific PRP receptors have been characterized in nonmammalian species, a specific PRP receptor has not been isolated in mammals. PRP receptor mRNA was widely detected in the brain, pituitary, and peripheral tissues. PRP has the potential to stimulate GH release from anterior pituitary cells, but this potency is lower in chickens and lost in mammals.