Studies of luminal and mucosal pH in reflux esophagitis and antral gastritis.

Luminal and mucosal pH were measured endoscopically in patients with reflux esophagitis and antral gastritis and in control subjects. In all subjects, significant lumen-to-mucosa gradients were observed in the esophagus, stomach and acidified proximal duodenum. In the reflux patients luminal pH was lower in the fundus (mean +/- SEM, control vs. reflux esophagitis: 2.01 +/- 0.17 vs. 1.32 +/- 0.18; p less than 0.02) and antrum (3.51 +/- 0.35 vs. 2.13 +/- 0.24; p less than 0.01) and, in the gastritis patients, in the fundus (2.01 +/- 0.17 vs. 1.3 +/- 0.17; p less than 0.02). In both patient groups, mucosal pH was lower in the fundus (control vs. reflux vs. gastritis: 4.84 +/- 0.37 vs. 3.37 +/- 0.61 vs. 3.12 +/- 0.6; p less than 0.05) and acidified duodenal cap (6.74 +/- 0.13 vs. 6.09 +/- 0.24 vs. 5.73 +/- 0.46; p less than 0.03). Mucosal pH profiles at the various sites showed less resistance of the gradient to a highly acidic environment in both the lower esophagus and antrum than in fundus and duodenum, and this was the case in the patient and control groups. Though associated with a more acid environment, neither esophagitis nor antral gastritis exhibits a specific deficit in the 'mucus-bicarbonate barrier', suggesting that the pathogenesis of these disorders may depend more on abnormal 'attack' rather than impaired defense.