The gastric
hormone gastrin stimulates gastric acid secretion and epithelial cell proliferation. Multiple active products are generated from the precursor,
preprogastrin, including the well-characterized amidated
gastrins acting at the cholecystokinin-2 (CCK-2, or gastrin-CCK(B)) receptor, and others that may be
growth factors in a range of
cancers. Plasma concentrations of the amidated
gastrins are elevated as a consequence of
gastrin-secreting tumours (
gastrinomas) and in conditions in which the normal inhibition of the
antral G-cell by
acid is depressed, for example chronic
atrophic gastritis and prolonged treatment with
proton pump inhibitors. There may also be increased
gastrin release in Helicobacter pylori
infection. Provocative tests for the diagnosis of
gastrinoma include the
secretin and
calcium infusion tests. Hypergastrinaemia is associated with enterochromaffin-like (ECL) cell proliferation; the factors that determine progression to ECL cell dysplasia and gastric ECL cell
carcinoid tumours are discussed. Several strategies for inhibiting the effects of
gastrin are under evaluation, and their potential application is discussed.