11.   Serum gastrin concentrations may also rise with age, probably because of the increased prevalence of gastric atrophy with consequent loss of acid mediated inhibition of gastrin release.

12.   Gastritis with atrophy and the consequent loss of acid mediated inhibition of gastrin release contributes most to this increase.

13.   The interactions of H pylori with gastrin release and gastric acid secretion are complex and seem to depend, in part, on the duration of infection.

14.   There is also evidence that gastrin release returns to normal after successful treatment of H pylori infection.

15.   Several investigators have discovered ablation of the exaggerated gastrin release after eradication of H pylori.

16.   Future studies evaluating mechanisms of gastrin release have to take into account the H pylori state.

17.   Firstly, H pylori could increase gastrin release by production of ammonia through its enzyme urease.

18.   This would raise the pH within the antrum mucus layer, which in turn would prevent inhibition of gastrin release through a feedback mediated mechanism by low intragastric acidity.

19.   Profound acid inhibition, however, results in increases in serum gastrin because of interference in the feedback mechanism between intragastric acidity and antral gastrin release.

20.   The increased antral gastrin release is explained by the H pylori infection though the mechanism by which the infection stimulates gastrin release is unknown.