Hepatic Porphyrin Synthesis in Rats After Pretreatment with Polychlorinated Biphenyls (PCBs)
| Autor: | H.F. Benthe, Achim Schmoldt, Wynand Grote |
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| Rok vydání: | 2009 |
| Předmět: |
Male
medicine.medical_specialty Porphyrins Time Factors chemistry.chemical_element Toxicology chemistry.chemical_compound Internal medicine Mole medicine High doses Chlorine Animals heterocyclic compounds Enzyme inducer Pharmacology Dose-Response Relationship Drug biology Chemistry Polychlorinated Biphenyls Porphyrin Stimulation Chemical Rats Kinetics Endocrinology Liver Biochemistry Dehydratase Porphyrin synthesis biology.protein After treatment 5-Aminolevulinate Synthetase |
| Zdroj: | Acta Pharmacologica et Toxicologica. 36:215-224 |
| ISSN: | 0001-6683 |
| Popis: | A single dose of polychlorinated biphenyls caused an increase of δ-aminolevulinic acid synthetase activity and porphyrin content in rat liver. δ-aminolevulinic acid dehydratase activity was not altered significantly. A maximum effect was obtained 24 hrs after treatment, and the rate limiting enzyme of porphyrin synthesis returned to a normal level of activity at the third day after treatment. On the contrary the porphyrin content of the liver remained elevated up to 4 weeks after a single injection of polychlorinated biphenyls. After administration of polychlorinated biphenyls the kinetic properties of δ-aminolevulinic acid synthetase of rat liver were found to be altered: an increase of Vmax was accompanied by a decrease of Km. The threshold dose for an increase of δ-aminolevulinic acid synthetase activity and porphyrin content of rat liver after a single dose of polychlorinated biphenyls was about 0.019 mmol/kg body weight for starved animals. At this dose range no significant differences in response of the parameters examined were seen when polychlorinated biphenyls with variable chlorine contents were administrated. A maximum effect for δ-aminolevulinic acid synthetase was obtained by a threefold dose, and no further increase was obtained by much higher doses, whereas increasing response up to these high doses was seen for the porphyrin content of the liver. At high doses the activity of δ-aminolevulinic acid synthetase increased with increasing chlorine content of the polychlorinated biphenyls. |
| Databáze: | OpenAIRE |
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