Cell specific activation of benzo(a)pyrene by fibroblasts and hepatocytes. [Rats]
The cell specific activation of benzo(a)pyrene (BP) by embryonic fibroblasts and by mature hepatocytes to intermediates that can interact with DNA, or cause mutations in Chinese hamster V79 cells has been investigated. At BP concentrations of up to 15..mu..M, BP was activated to mutagenic intermediates for the V79 cells by embryonic fibroblasts but not by hepatocytes. However, hepatocytes from rats that had been pretreated with an inducer of the mixed function oxidases, 3-methylcholanthrene, did metabolize higher doses of BP (<15 ..mu..M) to mutagenic intermediates. BP was extensively metabolized by both cell types, but the hepatocytes and fibroblasts showed differences both in the profiles of BP metabolites and the nature of the BP-DNA adducts formed. Hepatocytes metabolized BP principally to 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene, phenols, and quinones, which underwent further metabolism to water-soluble metabolites. Metabolism of BP to 7,8-dihydro-7,8-dihydroxybenzo(a)-pyrene (BP-7,8-diol) occurred but proceeded rapidly to the formation of triols and tetraols. Fibroblasts metabolized BP predominantly toward the formation of BP-7,8-diol. The proportion of primary metabolites undergoing further metabolism to conjugates was less extensive than in the hepatocytes. Hepatocytes bound more BP to their DNA than the fibroblasts. In the hepatocytes the major DNA adducts formed were hydrophilic derivatives, and no (+/-)7..beta..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) adducts were detected even after treatment with BP-7,8-diol. In the fibroblasts, the major BP - DNA adduct was derived from the reaction of BPDE with deoxyguanosine.
- Research Organization:
- Argonne National Lab., IL
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6250292
- Journal Information:
- Carcinogenesis (N.Y.); (United States), Journal Name: Carcinogenesis (N.Y.); (United States) Vol. 4:11; ISSN CRNGD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560301* -- Chemicals Metabolism & Toxicology-- Cells-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
ANIMAL CELLS
AROMATICS
BENZOPYRENE
CHO CELLS
COMPARATIVE EVALUATIONS
CONDENSED AROMATICS
CONNECTIVE TISSUE CELLS
DNA ADDUCTS
EMBRYONIC CELLS
FIBROBLASTS
HYDROCARBONS
LIVER CELLS
METABOLIC ACTIVATION
METABOLISM
METABOLITES
MUTAGENESIS
ORGANIC COMPOUNDS
POLYCYCLIC AROMATIC HYDROCARBONS
SENSITIVITY
SOMATIC CELLS