PREVENTIVE ACTIONS OF N-(3-AMINOPROPIONYL)-L-HISTIDINATO ZINC (Z-103) THROUGH INCREASES IN THE ACTIVITIES OF OXYGEN-DERIVED FREE-RADICAL SCAVENGING ENZYMES IN THE GASTRIC-MUCOSA ON ETHANOL-INDUCED GASTRIC-MUCOSAL DAMAGE IN RATS

Z-103 at 1 to 25 mg/kg, p.o. prevented 100% ethanol-induced gastric mucosal lesions in a dose-dependent manner. Z-103 at 3 to 25 mg/kg, p.o. significantly elevated gastric mucosal superoxide dismutase (SOD)-like activity 1 hr after its administration to normal rats. In addition, Z-103 at doses (10 and 25 mg/kg, p.o.) which prevented 100% ethanol-induced gastric lesion further increased gastric mucosal SOD-like and glutathione peroxidase (GSH-px) activities elevated by 60% ethanol. Z-103 (10 and 25 mg/kg) significantly inhibited the increase in thiobarbituric acid-reactive substances in gastric mucosa injured by 60% ethanol. The combination with cycloheximide, a protein synthesis inhibitor, completely abolished the prevention of 60% ethanol-induced gastric mucosal lesions and the elevation of both free radical scavenging enzyme activities in the mucosa by Z-103 (10 mg/kg, p.o.). These results suggest that Z-103 may partly protect rat gastric mucosa against ethanol-induced damage by scavenging oxygen-derived free radicals via increases in the synthesis of SOD-like and GSH-px enzymes in the mucosa.