title: Environmental polychlorinated biphenyls: acute toxicity of landfill soil extract to female prepubertal rats.
abstract: Subsurface soil from a National Priorities List landfill containing about 2.5% polychlorinated biphenyls (PCBs) was extracted and the extract cleaned by Florisil slurry and alumina column chromatography. The refined extract contained 48 mg/mL PCB, mainly trichlorobiphenyls and tetrachlorobiphenyls, traces of polychlorinated naphthalenes, 125 micrograms/mL 2,2-bis-p-chlorophenyl-1,1-dichloroethylene (DDE), and low levels of chlorinated dibenzofurans. The refined extract was dissolved in corn oil and administered intraperitoneally to weanling (day 20) female rats on days 20 and 21; rats were terminated on day 22. Limited data indicated possible hematopoietic effects, including neutrophilia. There were no changes in relative uterus, kidney, or adrenal gland weights between total doses of 3 to 96 mg/kg total PCB. Relative liver weights increased significantly at 36 mg/kg and activities of P450s 1A1 (as ethoxyresorufin O-dealkylase) and 2B (as pentoxyresorufin O-dealkylase) increased at 12 mg/kg and plateaued at 36 (P450 1A1) or 48 (P450 2b) mg/kg. Serum total thyroxine (T4) declined significantly at doses of 36 mg/kg and greater; thyroid follicular epithelial cells were significantly larger within the same dose range, but the follicular colloid area decreased to less than 60% control values at 12 mg/kg and remained at this size through 72 mg/kg. Maximum mobilization of T4 apparently occurred at 12 mg/kg and attenuated measured declines in circulating levels. Even though a large proportion of proven and probable estrogenic chlorobiphenyls (CBs) were present, the lower amounts of more potent antiestrogenic aryl hydrocarbon (Ah) receptor agonists and/or decreased responsiveness because of low serum T4 levels may have antagonized the uterotropic response.
mesh_terms: D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001572:Benzofurans / Q000008:administration & dosage / Q000633:toxicity*; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D000072338:Dibenzofurans, Polychlorinated; D003633:Dichlorodiphenyl Dichloroethylene / Q000008:administration & dosage / Q000633:toxicity*; D004781:Environmental Exposure; D005260:Female; D007274:Injections, Intraperitoneal; D007306:Insecticides / Q000008:administration & dosage / Q000633:toxicity*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D009504:Neutrophils / Q000187:drug effects; D009929:Organ Size / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity*; D000072317:Polychlorinated Dibenzodioxins / Q000008:administration & dosage / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013974:Thyroxine / Q000097:blood; D014018:Tissue Distribution; D014599:Uterus / Q000187:drug effects / Q000378:metabolism
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D007306:Insecticides; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; D003633:Dichlorodiphenyl Dichloroethylene; D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D013974:Thyroxine