Effect of antacid and H2-receptor blocker treatment on gastric endocrine cells

It has been previously suggested that antral pH governs the density of antral G- and D-cells. Therefore, we investigated the effect of acid neutralization by an antacid (magaldrat; in vivo neutralization capacity of 144 mval/day) and the effect of suppression of gastric acid secretion by an H2-receptor blocker (oxmetidine, 400 mg/day) on the density of both cell types in healthy volunteers and duodenal ulcer patients. Four weeks after antacid treatment antral G-cell density decreased significantly in both groups, while antral D-cells decreased only in volunteers. Basal serum gastrin was not altered, whereas the integrated postprandial serum gastrin response and antral gastrin concentration was significantly reduced in volunteers but not in ulcer patients. None of the parameters investigated was changed by oxmetidine treatment. Considering the short-lasting effect on acid neutralization induced by the antacid dosage used in this study and the inability of oxmetidine treatment to influence volume densities and secretory activities of antral G- and D-cells it is concluded that mechanisms other than a change of antral pH may account for the results obtained during antacid treatment.