Multiple dose toxicokinetic influence on the estrogenicity of 2,2[prime],4,4[prime],5,5[prime]-hexachlorobiphenyl

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Bulletin of Environmental Contamination and Toxicology; (United States)

OSTI ID:6645869

Li, M H; Zhao, Y D; Hansen, L G ^[1]

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1. Univ. of Illinois, Urbana, IL (United States)

Accurate assessment of polychlorinated biphenyl (PCB) hazards remains a challenge because of multiple effects and multiple components of PCB mixtures. A given chlorobiphenyl (CB) in an environmental residue may antagonize and/or potentiate the effects of other CBs in the mixture; furthermore, PCBs can induce biotransformation enzymes which can qualitatively as well as quantitatively alter the action(s) of individual CBs. Dose:response relationships of even single CBs may well be nonlinear due to these changes. Therefore, important effects may not be detected depending on the dose of the CB. There is growing public health concern regarding the potential risk from exposure to environmental estrogens. In a recent epidemiological study a significant positive association was reported between levels of 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE) in blood and risk of breast cancer; a positive, but nonsignificant association, was also observed for PCBs. Studies clearly suggest that the estrogenicity of PCBs is not related to potency as Ah receptor agonists. Therefore, it is important to investigate the estrogenicity of environmentally abundant ortho-chlorinated CB congeners in order to more accurately predict the hazards from PCB residues in the environment. Examination of alternative effects simultaneously and investigation of the possible interactions among these effects is important. Only a few congener-specific effects on thyroxine (T4) level have been reported, but it appears that coplanar CBs are the most effective. Therefore, both TCDD-like effects (EROD induction and thyrotoxic effect) and non-TCDD-like effects (PROD induction and estrogenic activity) of a persistent di-ortho conformationally restricted CB congener (2,2[prime],4,4[prime],5,5[prime]-hexachlorobiphenyl, CB 153) and a commercial PCB mixture, Aroclor 1242, were examined in immature female Sprague-Dawley rats. 17 refs., 1 fig., 4 tabs.

• OSTI ID: 6645869
• Journal Information: Bulletin of Environmental Contamination and Toxicology; (United States), Vol. 53:4; ISSN 0007-4861
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ESTROGENS
BIOCHEMISTRY
POLYCHLORINATED BIPHENYLS
BIOLOGICAL EFFECTS
RATS
PHYSIOLOGY
THYROXINE
DOSE-RESPONSE RELATIONSHIPS
AMINO ACIDS
ANIMALS
AROMATICS
CARBOXYLIC ACIDS
CHEMISTRY
CHLORINATED AROMATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
HORMONES
MAMMALS
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PEPTIDE HORMONES
PROTEINS
RODENTS
STEROID HORMONES
THYROID HORMONES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology