Gastric mucosal protection and superoxide dismutase.

Diethyldithiocarbamate (DDC), an inhibitor of Cu,Zn-superoxide dismutase (SOD), at a dose of 500 mg/kg or aminotriazole (AT), an inhibitor of catalase, at a dose of 2,000 mg/kg reduced slightly gastric mucosal SOD activity, did not change gastric mucosal blood flow (GMBF), and did not cause gastric ulcers. However, when both DDC and AT were administered together, gastric mucosal SOD activity and GMBF remarkably decreased, and gastric ulcers appeared. Moreover, the administration of SOD attenuated gastric ulcer induced by DDC plus AT. These results suggested that SOD may play an important role in the gastric mucosal defense mechanisms against active oxygen species.