Effect of DL-buthionine-S,R-sulfoximine on 1,2-dimethyl-hydrazine-induced colonic tumors in rats.

The effect of DL-buthionine-S,R-sulfoximine (BSO), a specific inhibitor of glutathione biosynthesis, on colon tumor development was studied in rats. Weanling male Sprague-Dawley rats were randomly assigned to one of three groups following a week of adaptation. Group 1 rats received BSO (4.5 mM) daily in the drinking water one week before 1,2-dimethylhydrazine (DMH) injections and continued to receive BSO daily until sacrificed; group 2 rats received BSO (4.5 mM) after the last DMH injection, and continued to receive BSO daily until sacrificed; group 3 rats did not receive BSO. All experimental rats received 20 weekly subcutaneous injections of DMH (20 mg/kg body wt.) for colon tumor induction. The tumor incidence was lower in group 1 (54%) than in group 2 (97%) or group 3 (96%). The median tumor size is significantly smaller in group 1 (11 mm2) than group 3 (46 mm2). The group 2 had the largest median tumor size (65 mm2).