GAST and chronic atrophic gastritis: While atrophic gastritis as a cause of hypergastrinemia [26] can be ruled out by histopathology (none of the dogs included in this study had histopathologic evidence of atrophic gastritis), the possibility of antral G-cell hyperplasia [33] (a condition that has not been reported in dogs to date) or an effect of antral distention associated with delayed gastric emptying or even gastric outlet obstruction on serum gastrin concentrations in individual dogs cannot be excluded in our study.