The influence of sodium selenite on tumor induction by methylnitrosourea (MNU) in rats

The effect of sodium selenite on tumor induction by MNU was studied in 3 groups of 40 WE rats each. Group I received 10 intraperitoneal injections of 20 mg/kg b. w. MNU in intervals of 4 weeks and beginning with the 1st administration 4 ppm sodium selenite in the drinking water. Rats of group II and III were given only MNU or selenite, respectively. A slight but statistically not significant increase of tumors was found in group I as compared with group II. In group III tumors did not occur. Problems of the anticarcinogenic action of sodium selenite and other antioxidants are discussed.