Gastrin plays a central role in the regulation of acid secretion. It i
s released by meals in quantities sufficient to explain meal-stimulate
d acid secretion. Gastrin stimulates acid secretion mainly by releasin
g histamine from the enterochromaffin-like (ECL) cell. Whether gastrin
has any functional direct effect on the parietal cell remains to be s
hown. Gastrin stimulates not only the function but also the growth of
the ECL cell, and longterm hypergastrinemia may lead to ECL cell carci
noids. The role of the ECL cell in human gastric carcinogenesis is con
troversial, but it seems wise to avoid long-term iatrogen hypergastrin
emia especially in young persons. Interestingly, the oxyntic mucosal D
cell, on which gastrin has a negative trophic effect, may play a role
in gastric stump carcinoma, and thus hypogastrinemia may also dispose
to gastric cancer.