The antioxidative effects of vitamin C (VC) on the toxicity of potassium bromate (KBrO3), a food additive, were examined. Five-week-old SPF-SD male rats were fed the VC enriched diets (310, 1310 and 3310 μg/g) for 4 weeks, and KBrO3 was given in the drinking water for 4 weeks at concentration of 500 μg/ml, simultaneously. The results obtained were as follows : 1. The activities of alkaline phosphatase (EC 3.1.3.1, ALP) and γ-glutamyl transpeptidase (EC 2.3.2.2, γ-GTP) in the kidney cytosols were suppressed depending upon the concentration of VC in the diets, but the activities of glutamic pyruvic transaminase (EC 2.6.1.2, GPT) and glutamic oxaloacetic transaminase (EC 2.6.1.1, GOT) were not effected by the concentration of VC in the diets. 2. The thiobarbituric acid reactive substances (TBARS) contents in the kidney homogenate and serum were increased by the administration of KBrO3, and decreased by the coadministration of VC enriched diets. However, the TBARS contents in the liver were almost constant. These results suggested that the increase of TBARS contents in the kidney and serum is correlated with the administration of KBrO3 and that the protective effects of VC to the toxicity of KBrO3 were unremakable. However, the TBARS contents were decreased by the simultaneous administration of VC enriched diets.
