Abstract
Omeprazole is a potent, long acting inhibitor of gastric acid secretion. It acts by blocking the H+K+ATPase in the parietal cell. Intragastric neutralization causes a rise in serum gastrin levels and, after longer periods of time, hyperfunction of gastrin producing cells may result. Therefore, the effects and after-effects of oral omeprazole on fasting and meal stimulated serum gastrin and serum pepsinogen I levels were studied.