An endogenous 29-amino acid peptide that belongs to the secretin/glucagon superfamily of peptides; 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; expressed in vaginal, uterine cervical, uterine horn, fallopian tube, and ovarian tissues from the rat female genital tract; present in extracts of male testis tissue