title: Placental transfer and developmental toxicity of 2,2',4,4',5,5'-hexabromobiphenyl in B6C3F1 mice.
abstract: The 2,2',4,4',5,5' congener of hexabromobiphenyl (HBB) is the major constituent (55%) of a polybrominated biphenyl mixture that accidentally entered the human food chain through livestock feed. The embryotoxicity of HBB in B6C3F1 conceptuses was examined by adding 0, 100, 300, 500, 750, or 1000 ppm of HBB to the diet of pregnant C57BL/6J mice impregnated by C3H males. The females consumed HBB feed from Gestation Day (gd) 6 through 15. Pregnancy rates of plug-positive mice were adversely affected at greater than 300 ppm HBB (0 ppm = 77%, 100 = 73%, 300 = 55%, 500 = 49%, 750 = 42%, 1000 = 33%). Some pregnant dams died at dosages of 750 ppm (2 of 8). Body weight gain among the 300-ppm dams was reduced only on gd 15, indicating maternal toxicity, but it was indistinguishable from controls on gd 17. In the conceptuses HBB caused cleft palate and a cystic lesion in the region of the cerebellum at concentrations greater than or equal to 300 ppm. The nature of the cystic abnormality observed grossly could not be accurately defined, but it was probably in the meninges and was not associated with the brain ventricular system. In some HBB-exposed fetuses there were minor abnormalities of brain development, which were probably indicative of developmental delay rather than direct toxic effects on differentiation of specific regions of the brain. Thus, HBB affected embryonal development adversely only at exposure concentrations which caused toxicity in dams.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000002:abnormalities* / Q000187:drug effects / Q000473:pathology; D005260:Female; D005313:Fetal Death / Q000139:chemically induced; D005327:Fetal Resorption / Q000139:chemically induced; D005333:Fetus / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D008099:Liver / Q000187:drug effects; D008297:Male; D008431:Maternal-Fetal Exchange; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009929:Organ Size / Q000187:drug effects; D011075:Polybrominated Biphenyls / Q000032:analysis / Q000633:toxicity*; D011247:Pregnancy; D013723:Teratogens; D014018:Tissue Distribution
chemical_list: D011075:Polybrominated Biphenyls; D013723:Teratogens; C018566:2,4,5,2',4',5'-hexabromobiphenyl