The effect of intragastric ammonia production on titratable gastric acid output in Helicobacter pylori-infected patients with chronic gastritis.

The purpose of this study was to assess whether intragastric neutralization of HCl by ammonia in Helicobacter pylori-infected patients could meaningfully affect the titratable acid output as a measure of gastric acid secretion in a relation to the severity of infection. In 79 patients with different degrees of Helicobacter pylori infection and chronic gastritis, the basal acid output (BAO) and maximal acid output (MAO) after pentagastrin (6 microg/kg s.c.) was estimated. Cl- and NH4+ contents in these fractions were also assayed. H+/Cl- ratio in the MAO fraction was diminished in markedly infected patients (68.1 +/- 3.9%, vs 84.1 +/- 3.3% in noninfected patients; P < 0.005). Ammonium content was maximal in patients with marked infection (0.912 +/- 0.086 vs 0.149 +/- 0.034 mmol/hr in MAO [P < 0.001] and 0.475 +/- 0.063 vs 0.105 +/- 0.016 mmol/hr in BAO of noninfected patients [P < 0.001]), with intermediate values in mild and moderate infection. The NH4 +/(H+ + NH4+) ratio reached 27.01 +/- 7.34% in the BAO of moderately infected patients, vs 10.22 +/- 3.81% in noninfected patients (P = 0.05), and 7.25 +/- 1.06% in the MAO of markedly infected patients, vs 1.14 +/- 0.33% in noninfected patients (P < 0.001). The intragastric ammonia production affects the titratable acid output in Helicobacter pylori-infected patients dependent on the severity of infection. Therefore this factor should be taken into consideration in the evaluation of gastric secretory function in Helicobacter pylori-infected patients.