Relationship between the prevention of rat gastric erosions and the inhibition of acid secretion by prostaglandins.

The formation of gastric mucosal erosions induced by indomethacin in the rat was inhibited in a time- and dose-dependent manner by antisecretory prostaglandins, the methyl analogues of PGE2 being 400 times as active as the parent prostaglandin. PGA2, a methyl analogue of PGF2alpha and the H2-receptor antagonist metiamide, also inhibited erosion formation. There was a variable relationship between the doses required to inhibit erosions and to inhibit gastric acid secretion. In the anaesthetised rat, the low incidence of erosions with indomethacin was markedly increased by concurrent gastric perfusion with acid saline and taurocholate. This mucosal damage was inhibited by the methyl analogues of PGE2, suggesting protective actions on the mucosa other than inhibition of acid secretion.