Apelin, a new enteric peptide: localization in the gastrointestinal tract, ontogeny, and stimulation of gastric cell proliferation and of cholecystokinin secretion - Wang, G; Anini, Y; Wei, W; Qi, X; AM, O C; Mochizuki, T; Wang, H Q; Hellmich, M R; Englander, E W; Greeley, G H, Jr (Endocrinology, 2004)