Phthalate esters. II. Effects of inhaled dibutylphthalate on cytochrome P-450 mediated metabolism in rat liver and lung. 1984

F Walseth, and O G Nilsen

Male Sprague Dawley rats were exposed to dibutylphthalate (DBP) by inhalation with concentrations of 0.5, 2.5, and 7.0 ppm in the air for 5 days. The concentrations were considered relevant to human exposure. No quantitative changes were observed in liver microsomal cytochrome P-450 related enzymes, but significant increase was observed in the liver microsomal metabolism of benzo(a)pyrene and n-hexane, in the 2.5 ppm and 0.5 ppm groups, respectively. Inhaled DBP decreased in a dose-dependent way the lung microsomal concentration of cytochrome P-450 by as much as 63%, which was reflected in a significant reduction of the microsomal metabolism of n-hexane and benzo(a)pyrene in the 7.0 ppm group. It is concluded that DBP in doses relevant to human air exposure influences the cytochrome P-450 enzyme system in both liver and lung, with lung as the main target organ. The observed effects in lung microsomes were similar to those earlier reported after IP administration of high doses of DBP.

UI MeSH Term Description Entries
D008099 Liver A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances. Livers
D008168 Lung Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood. Lungs
D008297 Male Males
D010795 Phthalic Acids A group of compounds that has the general structure of a dicarboxylic acid-substituted benzene ring. The ortho-isomer is used in dye manufacture. (Dorland, 28th ed) Acids, Phthalic
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003577 Cytochrome P-450 Enzyme System A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism. Cytochrome P-450,Cytochrome P-450 Enzyme,Cytochrome P-450-Dependent Monooxygenase,P-450 Enzyme,P450 Enzyme,CYP450 Family,CYP450 Superfamily,Cytochrome P-450 Enzymes,Cytochrome P-450 Families,Cytochrome P-450 Monooxygenase,Cytochrome P-450 Oxygenase,Cytochrome P-450 Superfamily,Cytochrome P450,Cytochrome P450 Superfamily,Cytochrome p450 Families,P-450 Enzymes,P450 Enzymes,Cytochrome P 450,Cytochrome P 450 Dependent Monooxygenase,Cytochrome P 450 Enzyme,Cytochrome P 450 Enzyme System,Cytochrome P 450 Enzymes,Cytochrome P 450 Families,Cytochrome P 450 Monooxygenase,Cytochrome P 450 Oxygenase,Cytochrome P 450 Superfamily,Enzyme, Cytochrome P-450,Enzyme, P-450,Enzyme, P450,Enzymes, Cytochrome P-450,Enzymes, P-450,Enzymes, P450,Monooxygenase, Cytochrome P-450,Monooxygenase, Cytochrome P-450-Dependent,P 450 Enzyme,P 450 Enzymes,P-450 Enzyme, Cytochrome,P-450 Enzymes, Cytochrome,Superfamily, CYP450,Superfamily, Cytochrome P-450,Superfamily, Cytochrome P450
D003993 Dibutyl Phthalate A plasticizer used in most plastics and found in water, air, soil, plants and animals. It may have some adverse effects with long-term exposure. Butyl Phthalate,Di-n-Butyl Phthalate,Di n Butyl Phthalate,Phthalate, Butyl,Phthalate, Di-n-Butyl,Phthalate, Dibutyl
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
D001564 Benzo(a)pyrene A potent mutagen and carcinogen. It is a public health concern because of its possible effects on industrial workers, as an environmental pollutant, an as a component of tobacco smoke. 3,4-Benzopyrene,3,4-Benzpyrene,3,4 Benzopyrene,3,4 Benzpyrene
D001580 Benzopyrenes A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it. Benzpyrene

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