In utero and lactational exposures to low doses of polybrominated diphenyl ether-47 alter the reproductive system and thyroid gland of female rat offspring

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are capable of disrupting thyroid hormone homeostasis. PBDE-47 (2,2',4,4'-tetrabromodiphenyl ether) is one of the most abundant congeners found in human breast adipose tissue and maternal milk samples. OBJECTIVES: We evaluated the effects of developmental exposure to low doses of PBDE-47 on the female reproductive system. METHODS: Pregnant Wistar rats were administered vehicle (peanut oil) or PBDE-47 [140 or 700 mu g/kg body weight (bw)] on gestation day (GD) 6, or 5 mg 6-n-propyl-2-thiouracil (PTU)/L in the drinking water from GD7 through postnatal day (PND) 21. RESULTS: In female offspring sacrificed on PND38, there was a significant decrease in ovarian weight after exposure to PTU or 140 mu g/kg PBDE-47. Alterations in folliculogenesis were apparent: we observed a decrease in tertiary follicles and serum estradiol concentrations in the offspring exposed to either PTU or 700 mu g/kg PBDE-47. PTU exposure also resulted in a decrease in primordial follicles. On PND 100, persistent effects on the thyroid glands included histologic and morphometric changes after exposure to either PTU or PBDE-47. No relevant changes in reproductive indices were observed after mating the exposed F-1 females with nontreated males. CONCLUSIONS: Administration of PBDE-47 at doses relevant to human exposure led to changes in the rat female reproductive system and thyroid gland.