Effects of Short-Term in Vivo Exposure to Polybrominated Diphenyl Ethers on Thyroid Hormones and Hepatic Enzyme Activities in Weanling Rats

We examined thyroid hormone concentrations and hepatic enzyme activity in weanling rats exposed to three commercial

T. Zhou


Scholarcy highlights

  • National Health and Environmental Effects Research Laboratory, U.S Environmental Protection Agency, Research Triangle Park, North Carolina 27711
  • Serum total T 4 was decreased a maximum of 80% for DE-71 and 70% for DE-79 in the highest dose, with benchmark doses of approximately 12.74 mg/kg/day for DE-71 and 9.25 mg/kg/day for DE-79
  • The present study suggests that short-term exposure to some commercial Polybrominated diphenyl ethers mixtures interferes with the thyroid hormone system via upregulation of UDPGTs
  • DE-71 and DE-79 caused hypothyroxinemia in weanling female rats following a 4-day exposure. This finding is consistent with other short-term and long-term studies on technical or pure PBDEs in rodents
  • The reduction in T 4 and T 3 was coincident with the induction of hepatic phase I enzymes CYP1A1, CYP2B
  • DE-83R, which consists of more than 98% of the highly brominated deca-BDE, had no significant effects on levels of thyroid hormones or UDPGT activity
  • DE-83R was ineffective in altering levels of serum thyroid hormones or hepatic EROD, PROD, or UDPGT activity, most likely due to the limited absorption of this highly brominated mixture

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