– PACAP-related peptide (PRP) is an endogenous 29-amino acid peptide that belongs to the secretin/glucagon superfamily of peptides, which includes secretin , glucagon , glucagon-like peptide-1 , GLP-2 , and pituitary adenylate cyclase-activating polypeptide . It is expressed in rat hypothalamus as well as within the nerves of the median eminence, the anterior pituitary, bed nucleus of the stria terminalis, cerebellum, cerebral cortex, and amygdala. PRP is also expressed in vaginal, uterine cervical, uterine horn, fallopian tube, and ovarian tissues from the rat female genital tract and is present in extracts of male testis tissue.