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PERINATAL EXPOSURE TO A POLYBROMINATED DIPHENYL ETHER MIXTURE (DE-71): DISRUPTION OF THYROID HOMEOSTASIS AND NEUROBEHAVIORAL DEVELOPMENT.
Citation:
Taylor, M. M., J M. Hedge, M. E. Gilbert, M J. DeVito, AND K M. Crofton. PERINATAL EXPOSURE TO A POLYBROMINATED DIPHENYL ETHER MIXTURE (DE-71): DISRUPTION OF THYROID HOMEOSTASIS AND NEUROBEHAVIORAL DEVELOPMENT. Presented at Society of Toxicology 42nd Annual Meeting, Salt Lake City, UT, March 9-13, 2003.
Description:
Polybrominated diphenyl ethers (PBDEs), produced commercially as mixtures, are used as flame-retardants in numerous consumer products. Previous work has demonstrated that the DE-71 induces hypothyroxinemia in both adults and developing rats. In these studies, primiparous rats were orally administered DE-71 (1 - 100mg/kg/day) in 1.0 ml/kg corn oil from gestation day 6 (GD6) to postnatal day 21 (PND21). Offspring were evaluated at various ages for survival, body weight, serum thyroid hormones, age of eye opening, motor activity development, hepatic enzyme activity (EROD, PROD, UDPGT), auditory startle, auditory thresholds, and fear conditioning. There was no effect of DE-71 on body weight gain or survival in either the dams or offspring. There were dose-dependent decreases in thyroxine in offspring relative to controls on PND 5 (73.3, 49.3 and 43.5 % of control) as well as on PND 14 (75.6, 33.6 and 29.9%) for 5, 30 and 100mg/kg respectively. DE-71 caused increases in hepatic EROD, PROD and UDPGT activity in both offspring and dams. Motor activity and startle were unaffected by treatment. Tests of fear conditioning revealed a dose-dependent decrease in cue- but not context-based performance in male offspring tested as adults. There was no effect on fear conditioning performance in offspring tested as weanlings. Auditory thresholds are currently being evaluated. These data suggest that developmental exposure to DE-71 induces hepatic enzymes and hypothyroxinemia in both dams and offspring, and alters some aspects of offspring neurobehavioral development. This is an abstract of a proposed presentation and does not necessarily reflect U.S.EPA policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.