title: Effect of increasing Helicobacter pylori ammonia production by urea infusion on plasma gastrin concentrations.
abstract: It has been proposed that the hypergastrinaemia in subjects with Helicobacter pylori infection is caused by the action of the ammonia produced by the organism's urease activity on the antral G cells. To investigate this hypothesis we examined the effect on plasma gastrin of increasing the bacterium's ammonia production by infusing urea intragastrically to eight H pylori positive duodenal ulcer patients. After a 60 minute control intragastric infusion of dextrose solution at 2 ml/minute, a similar infusion containing urea (50 mmol/l) was continued for four hours. During the urea infusion, the median gastric juice urea concentration rose from 1.1 mmol/l (range 0.3-1.6) to 15.5 mmol/l (range 7.9-21.3) and this resulted in an increase in the ammonium concentration from 2.3 mmol/l (range 1.3-5.9) to 6.1 mmol/l (range 4.2-11.9) (p less than 0.01). This appreciable rise in ammonia production did not result in any change in the plasma gastrin concentration. The experiment was repeated one month after eradication of H pylori, at which time the median basal gastrin was 20 ng/l (range 15-25), significantly less than the value before eradication (30 ng/l range 15-60) (p less than 0.05). On this occasion, the gastric juice ammonium concentration was considerably reduced at 0.4 mmol/l (range 0.1-0.9) and the urea infusion did not raise the ammonium concentration or change the plasma gastrin concentration. In conclusion, augmenting H pylori ammonia production does not cause any early change in plasma gastrin.
authors.affiliation: University Department of Medicine, Western Infirmary, Glasgow.
authors.forename: R S
authors.initials: RS
authors.lastname: Chittajallu
authors.forename: W D
authors.initials: WD
authors.lastname: Neithercut
authors.forename: A M
authors.initials: AM
authors.lastname: Macdonald
authors.forename: K E
authors.initials: KE
authors.lastname: McColl
mesh_terms: D000328:Adult; D000641:Ammonia / Q000032:analysis / Q000378:metabolism*; D004381:Duodenal Ulcer / Q000097:blood*; D005260:Female; D005750:Gastric Juice / Q000737:chemistry; D005755:Gastrins / Q000097:blood*; D016480:Helicobacter pylori / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014508:Urea / Q000008:administration & dosage* / Q000032:analysis
chemical_list: D005755:Gastrins; D000641:Ammonia; D014508:Urea