11.   However, we have previously found that neither increasing, inhibiting, nor completely abolishing H pylori urease activity in man alters serum gastrin.

12.   Obviously, this differentiation can readily be made by measurement of serum gastrin.

13.   In these controls, gastric endoscopy, serum gastrin, and gastric acid secretion were normal.

14.   As with serum gastrin, neither age not sex influenced serum pepsinogen concentrations.

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

16.   Serum gastrin was measured by a sensitive and specific radioimmunoassay, as previously described.

17.   Helicobacter pylori raises serum gastrin but it is unclear whether this stimulates increased acid secretion.