A model study of the regulation of gastric acid secretion.

A computer simulation model is presented of the gastric phase regulation of gastric acid secretion in humans. The model is based on experimental data from the literature and includes terms representing gastric pH and gastric volume-dependent gastrin secretion, gastrin-dependent acid secretion, food storage in the stomach, and gastric emptying. We have explored the predictive value of the model in assessing the relative importance of gastric pH-dependent and gastric volume-dependent acid secretion mechanisms under various conditions. Similarly we have studied the role of gastric acid deregulation in achlorhydria, the Zollinger-Ellison syndrome, and duodenal ulcer, and the influence of the antacid drugs cimetidine and ranitidine under duodenal ulcer conditions. Model analysis of normal gastric acid regulation suggests that gastric volume-controlled acid secretion is of major importance during eating and predicts that pH-dependent gastrin secretion is of major importance in preventing excessively low pH levels between meals and during the night.