Relative refractoriness of guinea pigs to carcinogenesis by 5-nitrofurans

Guinea pigs were observed to be refractory to carcinogenesis by 3 different carcinogenic 5-nitrofurans administered at 0.1% of the diet for 50 weeks followed by 74 weeks of control diet. In view of the evidenced involvement of nitroreduction in the metabolic activation of 5-nitrofurans, it is of interest that guinea pig refractoriness is not due to a quantitative nitroreductase deficiency in guinea pig liver.