Hypo-acidity of gastric juice in chronic gastric ulceration caused by neutralisation.

Samples of gastric juice were aspirated every 15 minutes from 54 normal subjects and 31 patients with chronic gastric ulcers during a maximal histamine infusion test. The known tendency of patients with gastric ulcers to secrete a less acid gastric juice than that of normal subjects was confirmed. However, the hypo-acidity was related to the extent by which the total ionic concentration was less than the isotonic value of 328 mEq/l. On the assumption that such hypo-acidity was produced by the neutralisation of hydrogen ions by bicarbonate ions refluxing into the stomach from the duodenum, the data were corrected and resulted in a normal estimate of the hydrogen ion concentration in the gastric ulcer group. Independent corrections, according to the sodium content of refluxed duodenal juice, yielded similar results for the volume of gastric juice aspirated. It is concluded that while back-diffusion can explain the hypo-acidity of gastric juice in patients with gastric ulcers, duodenal reflux can explain both the hypo-acidity and the hypotonicity, and is therefore more likely to be the correct explanation.