The role of histamine and serotonin in gastric acid secretion: A comparative study in gastric and duodenal ulcer patients

Abstract

The inter‐relationship between histamine and serotonin (5HT) levels in gastric juice and their role in stomach acid secretion in gastric (GU) and duodenal ulcer (DU) patients were investigated. DU patients showed a relatively higher basal gastric acid secretion, but had lower histamine and 5HT levels in their gastric juice than those with GU; these amine levels reflected their release from the stomach wall into its lumen. Tetragastrin injection (5 μg/kg, i.m.) increased the gastric secretion of acid and histamine in DU patients; however, the increased release of 5HT into the gastric lumen was not as much as that seen in GU patients. This study suggests that the high basal gastric acid in DU cases is related to hyposecretion of 5HT (a possible physiological inhibitor of gastric acid secretion) in the stomach. Tetragastrin‐induced hypersecretion of gastric acid in DU patients may be due to a higher level of histamine in relation to significantly lower amounts of 5HT secreted from their stomachs. The reverse may apply to the mechanism for the relative hyposecretion of gastric acid in GU patients compared to those with DU.