INDOMETHACIN-INDUCED CHANGES IN MUCOSAL LYSOSOMAL-ENZYME ACTIVITY - EFFECT OF H-2 ANTAGONISTS

Indomethacin induced gastric damage in rats was accompanied by a decre ase in mucosal activities of three lysosomal enzymes tested, with seru m levels remaining unchanged. Petreatments with cimetidine (100 mg/kg b.w.) and ranitidine (30 mg/kg b.w.) were found partially to prevent t he decrease of N-acetylglucosaminidase and acid phosphatase, as well a s of beta-glucuronidase, while the latter was also prevented by famoti dine (10 mg/kg b.w.). All the H-2 antagonists tested reduced dose-depe ndently the extent of gastric injury induced by indomethacin and rever sed the changes in protein levels. The stabilisation of lysosomal memb ranes and thus the prevention of lysosomal leakage may be one of the f avourable additional mechanisms of antiulcer activity of H-2 antagonis ts.