[3H]Benzo(a)pyrene Metabolism in Tracheal Epithelial Microsomes and Tracheal Organ Cultures

Marc J. Mass, David G. Kaufman

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Abstract

In respiratory carcinogenesis studies in Syrian golden hamsters, tracheal epithelium is a target tissue for the development of tumors induced by polynuclear aromatic hydrocarbon carcinogens. For evaluation of the capacity for metabolism of these carcinogens in this target tissue, the conversion of the carcinogen benzo(a)pyrene (BP) to polar products was studied in tracheal organ cultures and in isolated tracheal microsomes. Microsomal BP metabolism was found to be inducible by pretreatment of tracheas with 5 μM BP in organ culture. The apparent Kmfor either the induced or constitutive BP monooxygenase was found to be between 1 and 2 μM. The values of the apparent Vmaxwere 31 and 86 pmol product formed per mg microsomal protein per min for the constitutive and induced enzymes, respectively. Isolated tracheal microsomes catalyzed the binding of [3H]BP to DNA in vitro. Analysis of metabolites produced by tracheal epithelial microsomes with high-pressure liquid chromatography showed that diols, quinones, and phenols of BP were the major metabolic products formed during 30-min incubations. After 24 hr the metabolites formed in tracheal organ cultures largely cochromatographed with tetrols, triols, and the trans-9, 10-dihydro-9-10-dihydroxybenzo(a)pyrene of BP. The disparity between metabolites produced in these two systems is presumed to be related to coupled secondary metabolic reactions that occur upon prolonged incubation in the intact cells of organ cultures.

LanguageEnglish (US)
Pages3861-3866
Number of pages6
JournalCancer Research
Volume38
StatePublished - 1978

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Benzo(a)pyrene
Organ Culture Techniques
Microsomes
Carcinogens
Quinones
Phenols
Polycyclic Aromatic Hydrocarbons
Mesocricetus
Mixed Function Oxygenases
Trachea
Carcinogenesis
Epithelium
Cell Culture Techniques
High Pressure Liquid Chromatography
DNA
Enzymes
Neoplasms
Proteins

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

[3H]Benzo(a)pyrene Metabolism in Tracheal Epithelial Microsomes and Tracheal Organ Cultures. / Mass, Marc J.; Kaufman, David G.

In: Cancer Research, Vol. 38, 1978, p. 3861-3866.

Research output: Contribution to journalArticle

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