2,4-Dichlorophenyl-p-Nitrophenyl Ether (TOK)

Abstract

In a two-generation reproduction study, rats were fed dietary levels of 0, 20, 100, and 500 ppm of 2,4 dichlorophenyl-p-nitrophenyl ether (TOK) (1.8 to 1.1 mg/kg/ day, 9.2 to 5.2 mg/kg/day, and 46 to 26 mg/kg/day, respectively). The survival of the offspring was not affected at the 0 and 20 ppm dietary levels. At the 100 ppm dietary level the survival of the offspring to weaning was reduced and at the 500 ppm dietary level no offspring survived the neonatal period in the two breedings of the first generation. In further studies rats were dosed during pregnancy either by stomach tube or by adding TOK to the diet. The reduction in the number of surviving litters was caused by poorly developed lungs in the exposed groups. Technical TOK had the same effect as 99% pure TOK. Furthermore, 2,7-dichlorodibenzodioxin, which may be a contaminant of TOK, does not affect the maturation process of the lungs when given at a dose of 0.04 mg/kg/day on days 7 to 15 of gestation.