The relationship between serum gastrin, gastric ulceration and basal acid output in the polyarthritic rat.

The relation between the incidence of gastric ulceration, basal acid output and serum gastrin concentration was studied in the pyloric-ligated normal rat and the rat with established adjuvant disease (polyarthritis). Although there was no significant difference in either gastric secretions or basal acid output, serum gastrin was significantly higher in the adjuvant rat than in the normal rat, independent of the nutritional state of the animal. The incidence of the gastric lesions was eight times greater in adjuvant rats compared to controls in a 6-hour pyloric-ligation period. When the period of pyloric ligation was increased from 6 to 17 hr, there was 91% increase in gastric lesions in polyarthritic rats. Histopathology of the lesions in the polyarthritic rat showed diffuse and focal submucosal edema with polymorphonuclear inflammatory cell infiltration in the submucosa of the fundic and antral areas of the stomach. The increased susceptibility of the polyarthritic rat to gastric ulceration could be related to a combination of experimental stress and hypergastrinemia. Since similar elevations in serum gastrin have been reported in the rheumatoid arthritis in man, it is herein proposed that the polyarthritic rat could be used as a screening model for the evaluation of the ulcerogenicity potential of nonsteroidal anti-inflammatory drugs.