Reproductive Toxicity of Butylated Triphenyl Phosphate and Tricresyl Phosphate Fluids in F344 Rats

The effects of tricresyl phosphate (TCP) and butylated triphenyl phosphate (BTP)-based hydraulic fluid on reproduction were studied in F344 rats using a modification of the National Toxicology Program's Continuous Breeding Protocol. Groups of breeding pairs received single daily oral doses of an equal volume of either 0, 0.6, 1.0 g BTP/kg or 0.4 TCP/kg in sesame oil or 1.7 g neat BTP/kg for up to 135 days. A naive control group allowed to breed, but not dosed or handled daily, demonstrated that daily dosing and handling of the rats had no effect on reproduction. The fertility index and number of litters born were significantly decreased in rats exposed to 1.0 and 1.7 g BTP/kg and 0.4 g TCP/kg. The number of pups per litter was significantly decreased in the TCP group. A crossover mating experiment using 0.4 g TCP/kg/day and 1.0 g BTP/kg/day groups, each mated with vehicle controls, demonstrated that TCP caused 100% infertility in male rats but did not affect reproduction in females. BTP caused a significant decline in reproduction in female rats characterized by low mating and fertility indices, decreased number of litters, and abnormal estrous cycles. Fertility was decreased in the BTP-dosed male rats. Both sexes of rats in the crossover experiment with TCP and BTP had significant decreases in terminal body weights and increases in adrenal gland and liver weights. Only TCP-dosed male rats had significantly decreased testicular and epididymal weights.(ABSTRACT TRUNCATED AT 250 WORDS)