DOSE-RELATED ENHANCING EFFECT OF POTASSIUM BROMATE ON RENAL TUMORIGENESIS IN RATS INITIATED WITH N-ETHYL-N-HYDROXYETHYLNITROSAMINE

Abstract

Dose-response studies were undertaken to investigate the enhancing activity of KBRO3, a food additive, on renal tumorigenesis initiated by N-ethyl-N-hydroxyethylnitrosamine (EHEN). A total of 180 male 6-wk-old F344 rats were divided into 12 groups. EHEN was given in the drinking water for the first 2 wk at a concentration of 500 ppm for initiation of carcinogenesis. Thereafter, the rats were treated orally either with KBrO3 at a concentration of 500, 250, 125, 60, 30 or 15 ppm, or KBr at a concentration of 1750 or 350 ppm for 24 wk. The mean numbers of kidney dysplastic foci were significantly increased in a dose-related manner in rats treated with > 30 ppm KBrO3. The mean number of renal cell tumors was significantly higher after treatment KBrO3 at the highest concentration of 500 ppm; KBr had no effect. KBrO3 at doses > 30 ppm in the drinking water apparently has an enhancing effect on renal tumorigenesis.