Background：Gastrin-releasing peptide, also known as GRP, is normally formed by mucosal cells in the gastric antrum and by the D cells of the pancreatic islets, and its main function is to stimulate secretion of HCl by the gastric mucosa. HCl, in turn, inhibits gastrin formation. Its 148-amino acid preproprotein, following cleavage of a signal peptide, is further processed to produce either the 27-amino acid gastrin-releasing peptide or the 10-amino acid neuromedin C. These smaller peptides regulate numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation.These peptides are also likely to play a role in human cancers of the lung, colon, stomach, pancreas, breast, and prostate.
