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Metabolism and Macromolecular Binding of Benzo(A)Pyrene and Its Noncarcinogenic Isomer Benzo(E)Pyrene in Cell Culture.

CONF7810394

Publication Date	1978
Personal Author	Selkirk, J. K.; MacLeod, M. C.
Page Count	28
Abstract	The carcinogenicity of the polycyclic aromatic hydrocarbon benzo(a)pyrene (B(a)P) is thought to result from the metabolic formation of a highly reactive intermediate, 7,8-dihydrodiol-9,10-oxy-B(a)P which subsequently interacts with cellular macromolecules to produce neoplasia. Evidence has been presented implicating similar bay-region diol-epoxides as the ultimate carcinogenic forms of benz(a)anthracene, 7-methyl-benz(a)anthracene, dibenz(a,h)anthracene, and chrysene. Benzo(e)pyrene (B(e)P), on the other hand, is relatively inert when tested for carcinogenicity on mouse skin and rat trachea and when tested for mutagenicity in a mammalian system. This B(e)P molecule contains two (equivalent) bay regions and quantum mechanical model calculations suggest that 9,10-dihydrodiol-11,12-oxy-B(e)P can easily form a reactive bay-region-adjacent carbonium ion. In order to explain the noncarcinogenicity of B(e)P in the context of the bay region theory, we have studied the metabolism of B(e)P by rat liver microsomes and by cultured hamster embryo fibroblasts. In both systems, the major metabolic pathways involve the K-region of B(e)P, with little or no attack on the isolated benzo ring. These results suggest that the lack of carcinogenicity of B(e)P may reflect its preferred mode of interaction with the cellular metabolic machinery. (ERA citation 04:014635)
Keywords	Benzopyrene Carcinogenesis Binding energy Cell cultures Comparative evaluations Embryos Fibroblasts Hamsters Isomers Liver Metabolism Metabolites Microsomes Rats ERDA/560301 ERDA/550300 ERDA/550200
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	57B - Biochemistry 57F - Cytology, Genetics, & Molecular Biology
Corporate Authors	Oak Ridge National Lab., TN.; Department of Energy.
Supplemental Notes	Symposium on polynuclear aromatic hydrocarbons, Columbus, OH, USA, Oct 1978.
Document Type	Technical Report
NTIS Issue Number	197910
Contract Number	W-7405-ENG-26

Metabolism and Macromolecular Binding of Benzo(A)Pyrene and Its Noncarcinogenic Isomer Benzo(E)Pyrene in Cell Culture.

Metabolism and Macromolecular Binding of Benzo(A)Pyrene and Its Noncarcinogenic Isomer Benzo(E)Pyrene in Cell Culture.
CONF7810394

Publication Date	1978
Personal Author	Selkirk, J. K.; MacLeod, M. C.
Page Count	28
Abstract	The carcinogenicity of the polycyclic aromatic hydrocarbon benzo(a)pyrene (B(a)P) is thought to result from the metabolic formation of a highly reactive intermediate, 7,8-dihydrodiol-9,10-oxy-B(a)P which subsequently interacts with cellular macromolecules to produce neoplasia. Evidence has been presented implicating similar bay-region diol-epoxides as the ultimate carcinogenic forms of benz(a)anthracene, 7-methyl-benz(a)anthracene, dibenz(a,h)anthracene, and chrysene. Benzo(e)pyrene (B(e)P), on the other hand, is relatively inert when tested for carcinogenicity on mouse skin and rat trachea and when tested for mutagenicity in a mammalian system. This B(e)P molecule contains two (equivalent) bay regions and quantum mechanical model calculations suggest that 9,10-dihydrodiol-11,12-oxy-B(e)P can easily form a reactive bay-region-adjacent carbonium ion. In order to explain the noncarcinogenicity of B(e)P in the context of the bay region theory, we have studied the metabolism of B(e)P by rat liver microsomes and by cultured hamster embryo fibroblasts. In both systems, the major metabolic pathways involve the K-region of B(e)P, with little or no attack on the isolated benzo ring. These results suggest that the lack of carcinogenicity of B(e)P may reflect its preferred mode of interaction with the cellular metabolic machinery. (ERA citation 04:014635)
Keywords	Benzopyrene Carcinogenesis Binding energy Cell cultures Comparative evaluations Embryos Fibroblasts Hamsters Isomers Liver Metabolism Metabolites Microsomes Rats ERDA/560301 ERDA/550300 ERDA/550200
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	57B - Biochemistry 57F - Cytology, Genetics, & Molecular Biology
Corporate Authors	Oak Ridge National Lab., TN.; Department of Energy.
Supplemental Notes	Symposium on polynuclear aromatic hydrocarbons, Columbus, OH, USA, Oct 1978.
Document Type	Technical Report
NTIS Issue Number	197910
Contract Number	W-7405-ENG-26