Comparison of gastric body and antral pH: a 24 hour ambulatory study in healthy volunteers.

Simultaneous ambulatory records of gastric antral and body pH were made over 24 hours in nine healthy volunteers by means of endoscopically positioned and anchored glass electrodes. Intragastric pH was temporarily raised after the endoscopy with the median pH value 30 minutes after the procedure being 3.9 (range 1.5-7.0) for the antrum and 4.1 (range 1.5-7.0) for the body. Daytime pH (median pH value between 12 00 h and 23 00 h) was lower in the antrum (median = 1.9, range 1.6-2.6) than in the body (median = 2.7, range 1.8-4.5) (p less than 0.05) and this was because of the rise in pH on eating being less marked in the antrum than in the body. The median peak pH recorded during the evening meal was only 4.1 (range 2.4-6.2) in the antrum compared with 6.3 (range 4.4-6.7) in the body (p less than 0.01). Preprandial pH (median value over the hour prior to the evening meal) was similar in the antrum (median = 1.9, range 1.2-2.5) and body (median = 1.9, range 1.3-2.8). Night-time pH (median pH value between 23 00 h and 05 00 h) in six subjects remained low and was similar in the antrum (median = 1.4, range 1.2-1.7) and body (median = 1.3, range 1.1-1.7). In two subjects, however, there were episodes of raised night-time pH which were more marked in the antrum than in the body. Antral biopsies showed gastritis in four of the nine normal volunteers, which in three was associated with the presence of campylobacter-like organisms. This study shows the significant regional variations in day and night-time intragastric pH.