Eradication of Helicobacter pylori Restores Glutathione S‐Transferase Activity and Glutathione Levels in Antral Mucosa

Glutathione S‐transferases (GST) and glutathione peroxidases (GPO) are important in detoxification. GST activity in the mucosa of the gastrointestinal tract is inversely correlated with the development of gastrointestinal cancer. Helicobacter pylori (H. pylori) infection has been associated with gastric cancer. We studied GST activity and the substrate glutathione (GSH) in patients with H. pylori‐associated gastritis. GST activity and isoenzyme levels, GPO activity and GSH levels were studied in antral biopsies of 38 H./pyfori‐positive patients, before and after eradication treatment. In 31 patients in whom H. pylori was successfully eradicated, antral GST enzyme activity before therapy was 532 (465–598) nmol/mg protein‐min (mean and 95% confidence interval) and that after therapy was 759 (682–836) nmol/mg protein‐min (P<0.0001). Correspondingly, levels of GST α and GST‐P1 were higher after eradication (P<0.001). GSH concentration significantly increased: 21.2 (16.2–26.2) nmol/mg protein before and 27.1 (23.6–30.6) nmol/mg protein after therapy (P<0.05). In 7 patients in whom H. pylori was not eradicated, GST activity was 671 (520–823) nmol/mg protein min and 599 (348–850) nmol/mg protein before and after treatment respectively (P=0.32). GSH levels were 17.4 (9.0–25.7) nmol/mg protein and 18.2 (9.1–27.3) nmol/mg protein, respectively (P=0.84). No differences in antral GPO enzyme activity, both of selenium (Se)‐dependent and total GPO, before and after successful treatment were found. Eradication of H. pylori infection increases GST activity and GSH levels in antral mucosa. Low GST activity and GSH concentration due to H. pylori infection might play a role in gastric carcinogenesis.