Gastrin-Releasing Peptide, human(TFA) is a regulatory human peptide that elicits gastrin release and regulates gastric acid secretion and enteric motor function. The post-ganglionic fibers of the vagus nerve that innervate the G cells of the stomach release GRP, which stimulates the G cells to release gastrin.

Gastrin-Releasing Peptide, human (GRP) belongs to the bombesin-like peptide family, and is not a classical hypothalamic-hypophyseal regulatory hormone since it plays only a perfunctory role in the mediation of pituitary hormone release. However, GRP/bombesin-like immunoreactivity is widely distributed in mammalian brain, especially the hypothalamus, GI tract and in human fetal lung[1].