Biomaterial Database

Induction effects of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and other widespread aromatic environmental pollutants on microsomal monooxygenase activities in chick embryo liver. 1996

M Machala, and L Mátlová, and I Svoboda, and K Nezveda

Veterinary Research Institute, Brno, Czech Republic.

Cytochrome P450-dependent 7-ethoxyresorufin O-deethylase (EROD), 7-pentoxyresorufin O-dealkylase (PROD) and 7-ethoxycoumarin O-deethylase (ECOD) activities in 14-day-old chick embryo livers were determined 24 h after pretreatment with selected widespread aromatic environmental contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorobenzene, and dialkylesters of phthalic acid, and compared with the inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the coplanar and mono-o-chlorinated PCBs. The effects of other model inducers, i.e. phenobarbital and pyrazole, were also examined. Specificity of EROD induction was estimated with regard to contaminants frequently present in environmental samples and dose-response curves for EROD induction were determined. A strong induction (comparable with that by mono-o-chlorinated biphenyl treatment) by dibenzo[a,h]anthracene, benzo[k]fluoranthene or benzo[b]fluoranthene was found, but the maximal level of EROD activity inducible by TCDD was not achieved, partly due to the high toxicity of the tested PAHs. 3-Methylcholanthrene showed moderate inducing potencies; benz[a]anthracene, benzo[a]pyrene, chrysene and 2,2',3,4,4',5'-hexachlorobiphenyl appeared to be weak inducers. Other PAHs and PCBs tested, as well as hexachlorobenzene, dialkyl phthalates, phenobarbital and pyrazole had no marked effects on the EROD level. ECOD activities were increased non-specifically by TCDD, 3-methylcholanthrene, hexachlorobenzene and phenobarbital. A significant enhancement of PROD activity by TCDD and related inducers was observed, while phenobarbital induced the PROD activity only weakly; SDS-PAGE analysis showed that the chicken phenobarbital-inducible cytochromes P4502H with apparent molecular weights 50 kDa were not markedly induced by the TCDD- or 3-methylcholanthrene treatments. Inhibition of EROD and PROD by 9-hydroxyellipticine, a specific inhibitor of rat hepatic cytochrome P4501A1, revealed that PROD induction by TCDD and other P4501A-inducers was probably a result of a broader substrate specificity of chick embryo P4501A. Measurement of EROD activities in chick embryo liver is highly sensitive, specific and suitable for the determination of TCDD-type toxicity of new drugs, agrochemicals, and industrial pollutants.

UI	MeSH Term	Description	Entries
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D011078	Polychlorinated Biphenyls	Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.	PCBs,Polychlorinated Biphenyl,Polychlorobiphenyl Compounds,Biphenyl, Polychlorinated,Biphenyls, Polychlorinated,Compounds, Polychlorobiphenyl
D011084	Polycyclic Aromatic Hydrocarbons	Aromatic hydrocarbons that contain extended fused-ring structures.	Polycyclic Aromatic Hydrocarbon,Polycyclic Hydrocarbons, Aromatic,Polynuclear Aromatic Hydrocarbon,Polynuclear Aromatic Hydrocarbons,Aromatic Hydrocarbon, Polycyclic,Aromatic Hydrocarbon, Polynuclear,Aromatic Hydrocarbons, Polycyclic,Aromatic Hydrocarbons, Polynuclear,Aromatic Polycyclic Hydrocarbons,Hydrocarbon, Polycyclic Aromatic,Hydrocarbon, Polynuclear Aromatic,Hydrocarbons, Aromatic Polycyclic,Hydrocarbons, Polycyclic Aromatic,Hydrocarbons, Polynuclear Aromatic
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D004785	Environmental Pollutants	Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.	Environmental Pollutant,Pollutant,Pollutants,Pollutants, Environmental,Pollutant, Environmental
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme
D000072317	Polychlorinated Dibenzodioxins	Dibenzodioxin derivatives that contain multiple chloride atoms bound to the benzene ring structures.	TCDD,Tetrachlorodibenzodioxin,2,3,7,8-Tetrachlorodibenzo-p-dioxin,Chlorinated Dibenzo-p-dioxins,Dibenzo(b,e)(1,4)dioxin, 2,3,7,8-tetrachloro-,PCDD,Polychlorinated Dibenzo-p-dioxins,Polychlorinated Dibenzodioxin,Polychlorodibenzo-4-dioxin,Polychlorodibenzo-p-dioxin,Tetrachlorodibenzo-p-dioxin,Chlorinated Dibenzo p dioxins,Dibenzo-p-dioxins, Chlorinated,Dibenzo-p-dioxins, Polychlorinated,Dibenzodioxin, Polychlorinated,Dibenzodioxins, Polychlorinated,Polychlorinated Dibenzo p dioxins,Polychlorodibenzo 4 dioxin,Polychlorodibenzo p dioxin,Tetrachlorodibenzo p dioxin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015660	7-Alkoxycoumarin O-Dealkylase	A drug-metabolizing enzyme found in the hepatic, placental and intestinal microsomes that metabolizes 7-alkoxycoumarin to 7-hydroxycoumarin. The enzyme is cytochrome P-450- dependent.	7-Ethoxycoumarin O-Dealkylase,7-Ethoxycoumarin O-Deethylase,7-Ethoxycoumarin Dealkylase,7-Ethoxycoumarin Hydroxylase,7-Ethoxycoumarin Monooxygenase,7-Ethoxycoumarin O-De-Ethylase,7-Propoxycoumarin O-Depropylase,Cytochrome P-450-Dependent O-Dealkylase,Ethoxycoumarin Deethylase,Ethoxycoumarin O-Deethylase,7 Alkoxycoumarin O Dealkylase,7 Ethoxycoumarin Dealkylase,7 Ethoxycoumarin Hydroxylase,7 Ethoxycoumarin Monooxygenase,7 Ethoxycoumarin O De Ethylase,7 Ethoxycoumarin O Dealkylase,7 Ethoxycoumarin O Deethylase,7 Propoxycoumarin O Depropylase,Cytochrome P 450 Dependent O Dealkylase,Dealkylase, 7-Ethoxycoumarin,Deethylase, Ethoxycoumarin,Ethoxycoumarin O Deethylase,Hydroxylase, 7-Ethoxycoumarin,Monooxygenase, 7-Ethoxycoumarin,O-Deethylase, 7-Ethoxycoumarin,O-Depropylase, 7-Propoxycoumarin,P-450-Dependent O-Dealkylase, Cytochrome