Inhibition of microsomal and mitochondrial Ca2+-sequestration in rat cerebellum by polychlorinated biphenyl mixtures and congeners
Autor: | Hugh A. Tilson, James D. McKinney, Prasada Rao S. Kodavanti, Thomas R. Ward |
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Rok vydání: | 1996 |
Předmět: |
Male
Health Toxicology and Mutagenesis Mitochondrion Toxicology Structure-Activity Relationship chemistry.chemical_compound Cerebellum Microsomes Animals IC50 Protein kinase C biology Polychlorinated biphenyl Rats Inbred Strains General Medicine biology.organism_classification Polychlorinated Biphenyls In vitro Mitochondria Rats Dibenzofuran Microsoma chemistry Biochemistry Microsome Calcium |
Zdroj: | Archives of Toxicology. 70:150-157 |
ISSN: | 1432-0738 0340-5761 |
Popis: | Recent studies from our laboratory indicate that polychlorinated biphenyl (PCB) congeners in vitro perturbed signal transduction mechanisms including cellular Ca2+-homeostasis and protein kinase C translocation. We have now investigated the structure-activity relationship (SAR) of three PCB mixtures, 24 PCB congeners and one dibenzofuran for their effects on microsomal and mitochondrial Ca2+-sequestration in rat cerebellum. Ca2+-sequestration by these intracellular organelles was determined using radioactive 45CaCl2. All three mixtures studied, Aroclor 1016, Aroclor 1254 and Aroclor 1260, were equally potent in inhibiting microsomal and mitochondrial Ca2+-sequestration with IC50 values of 6-8 microM. 1,2,3,7,8-Pentachlorodibenzofuran had no effect on Ca2+-sequestration by these organelles. The SAR among the congeners revealed: (1) congeners with ortho-/meta- or ortho-, para-chlorine substitutions were the most potent in inhibiting microsomal and mitochondrial Ca2+-sequestration (IC50 = 2.4-22.3 microM); (2) congeners with only para- but without ortho-substitutions were not effective in inhibiting Ca2+-sequestration by microsomes and mitochondria; (3) increased chlorination was not related to the effectiveness of these congeners. The present SAR studies indicate that the effects of most PCB congeners in vitro may be related to an interaction at specific sites having preference for low lateral substitution or lateral content (meta- or para) in the presence of ortho-substitution. |
Databáze: | OpenAIRE |
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