Effect of antacid treatment on endogenous prostaglandin synthesis in human antral and duodenal mucosa.

Using 14C-labeled arachidonic acid as precursor for in vitro prostaglandin synthesis, the effect of an antacid containing Al (OH)3, Mg(OH)2 and CaCO3 on endogenous prostaglandin synthesis was investigated in antral and duodenal mucosa of healthy volunteers. After three weeks of treatment with a high-dose antacid, there was no detectable change in the total capacity of the mucosa for prostaglandin synthesis, but the prostaglandin profile was markedly altered. The relative amounts of PGE2 and PGF2 alpha synthesized by antral and duodenal mucosa increased at the expense of the prostaglandins A2/B2, thromboxane A2, and prostacyclin. In a short-term study, this change was not observed following a single antacid dose within 1 hr after application. It is concluded that long-term antacid treatment may alter the prostaglandin pattern formed by gastroduodenal mucosa and this may be related to its therapeutic effect.