Indomethacin induced changes in mucosal lysosomal enzyme activity: effect of H2 antagonists.

Indomethacin induced gastric damage in rats was accompanied by a decrease in mucosal activities of three lysosomal enzymes tested, with serum levels remaining unchanged. Petreatments with cimetidine (100 mg/kg b.w.) and ranitidine (30 mg/kg b.w.) were found partially to prevent the decrease ofN-acetylglucosaminidase and acid phosphatase, as well as of beta-glucuronidase, while the latter was also prevented by famotidine (10 mg/kg b.w.). All the H2 antagonists tested reduced dose-dependently the extent of gastric injury induced by indomethacin and reversed the changes in protein levels. The stabilisation of lysosomal membranes and thus the prevention of lysosomal leakage may be one of the favourable additional mechanisms of antiulcer activity of H2 antagonists.