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Metabolism of Benzo(a)Pyrene and Benzo(a)Pyrene 4,5-Oxide in Rabbit Lung

  • John R. Bend
  • Brian R. Smith
  • Louise M. Ball
  • John L. Plummer
  • C. Roland Wolf
  • Richard M. Philpot
  • Theodora R. Devereux
  • James R. Fouts
Part of the Advances in Experimental Medicine and Biology book series (AEMB)

Abstract

For several years our laboratory has been investigating the biotransformation of various environmental pollutants by lung. Studies have been performed with pulmonary subcellular fractions, purified monooxygenase and glutathione transferase enzymes, and preparations having intact cellular structure including the isolated perfused lung and cell fractions enriched in alveolar macrophages, Clara cells and alveolar type II cells. Collectively, these investigations have identified several metabolic factors which may contribute to the pulmonary toxicity mediated by certain polycyclic aromatic hydrocarbons (PAH). First, although lung has low overall cytochrome P-450-dependent monooxygenase activity for many substrates, relative to liver, this activity is localized in only a few cell types and specific activity in certain cell types, such as the non-ciliated bronchiolar epithelial (Clara) cell, can be high. Second, oxidative metabolites of benzo(a)pyrene tend to accumulate in pulmonary tissue due, at least in part, to the low ability of lung (relative to liver) to conjugate and detoxify phenolic, dihydrodiol and epoxide metabolites. Thus, products such as benzo(a)pyrene 7,8-dihydrodiol are available for further cytochrome P-450-dependent oxidation to ultimate carcinogens and cytotoxins. Moreover, the lung is efficient in removing benzo(a)pyrene 4,5-oxide and presumably other oxidized PAH metabolites, from the bloodstream. Consequently, the uptake of relatively stable electrophilic metabolites released by the liver may also contribute to pulmonary toxicity.

Keywords

Polycyclic Aromatic Hydrocarbon Pulmonary Toxicity Epoxide Hydrolase Perfuse Lung Alveolar Type 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1982

Authors and Affiliations

  • John R. Bend
    • 1
  • Brian R. Smith
    • 1
  • Louise M. Ball
    • 1
  • John L. Plummer
    • 1
  • C. Roland Wolf
    • 1
  • Richard M. Philpot
    • 1
  • Theodora R. Devereux
    • 1
  • James R. Fouts
    • 1
  1. 1.Laboratory of Pharmacology National Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkUSA

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