Indomethacin decreases gastroduodenal mucosal bicarbonate secretion in humans.
BACKGROUND
Cyclooxygenase inhibitors reduce mucosal bicarbonate secretion in the duodenum, but the evidence for their effect on bicarbonate secretion in the stomach remains controversial. We have, therefore, studied how indomethacin influences gastroduodenal bicarbonate secretion and luminal release of prostaglandin (PG) E2 by means of a method that enables simultaneous measurements in the stomach and the duodenum.


METHODS
Gastric and duodenal perfusions were performed twice in random order during control conditions or after pretreatment with indomethacin (100 mg intravenously) in eight healthy volunteers. Bicarbonate and PGE2 were measured in the gastroduodenal effluents by back-titration and radioimmunoassay, respectively.


RESULTS
Vagal stimulation and duodenal luminal acidification (0.1 M HCl; 20 ml; 5 min) increased gastroduodenal bicarbonate secretion (p < 0.05). Indomethacin markedly inhibited both basal and stimulated gastric and duodenal mucosal bicarbonate secretion, and this reduction was similar to the degree of cyclooxygenase inhibition estimated by the luminal release of PGE2 (p < 0.05).


CONCLUSIONS
These results unequivocally demonstrate that endogenous PG modulates basal and stimulated bicarbonate secretion, both in the stomach and in the duodenum.
Mertz-Nielsen
A
A
Dept. of Medical Gastroenterology, University of Copenhagen, Denmark.
Hillingsø
J
J
Bukhave
K
K
Rask-Madsen
J
J
D000328:Adult; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone / Q000032:analysis / Q000502:physiology; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology*; D008297:Male; D017693:Sodium Bicarbonate / Q000378:metabolism*
D016861:Cyclooxygenase Inhibitors; D017693:Sodium Bicarbonate; D015232:Dinoprostone; D007213:Indomethacin