Changes in superoxide dismutase activity in the gastric mucosa of peptic ulcer patients.

A highly sensitive chemiluminescence method for determining superoxide dismutase (SOD) activities in human gastric mucosa obtained by endoscopic biopsy is described. As the chemiluminescence probe, we used Cypridina luciferin analogue (CLA), a very sensitive and specific probe to detect superoxide generated from hypoxanthine-xanthine oxidase system. SOD activity in the gastric mucosa was assayed by the inhibition of CLA-dependent chemiluminescence in highly diluted tissue homogenates. SOD activity was distributed throughout the gastric mucosa. The marginal mucosa of peptic ulcers showed significantly lower SOD activity when the ulcer was in the active stage, and during the healing stage showed high activity when compared to the endoscopically normal adjacent mucosa of the same patients. The preliminary data suggest that enzymatic SOD in the gastric mucosa may play an important role in the pathogenic and healing processes of human peptic ulcers.