Activities of Polycyclic Hydrocarbon Activating and Inactivating Enzymes in Human Lungs of Smokers, Non-Smokers, Lung-Cancer and Non-Cancer Patients

  • J. Lorenz
  • H. Schmassmann
  • E. Ohnhaus
  • F. Oesch
Part of the Archives of Toxicology book series (TOXICOLOGY, volume 2)


Human lungs are an important target organ for environmental carcinogenic polycyclic hydrocarbons (PAH), which can be metabolised by microsomal monooxygenases (MO) to mutagenic epoxides. The concentrations within the cells of these reactive epoxides, which are suspected ultimate carcinogens, will be controlled not only by the MO activities, but also by the epoxide inactivating epoxide hydratase (EH) and glutathione-S-transferase (GT) activities. To our knowledge no data exist on these enzyme activities in human lungs.

Therefore, we have investigated these enzyme activities and studied whether a correlation exists between these epoxide forming and inactivating enzyme activities and the occurrence of lung cancer by measuring these enzyme activities in 47 samples from lungs of smokers, non-smokers, lung-cancer and non-cancer patients. Using standard assays no MO activity could be detected, although the very sensitive assays with benzo(a)pyrene, 7-ethoxycoumarin, 7-ethoxyresorufm and biphenyl as substrates were used whilst these activities in rat lung microsomes used as positive controls were always clearly measurable. Evidence was obtained for the presence of a diffusible MO-inhibitor in human lung microsomes. Finally we succeded in measuring 7-ethoxycoumarin-0-dealkylase activity after modification of the assay. EH and GT activities were determined with benzo(a)pyrene 4,5-oxide, the latter was also measured with 2,4-dinitrochloro-benzene as substrate.

Considerable interindividual variations in enzyme activities were observed. However, no significant differences were found when the enzyme activities in lungs from non-cancer patients and non-smokers were compared with those in lung cancer patients.

The substrate specificity of human lung epoxide hydratase investigated using K-region epoxides of various PAH was similar to that in rat liver and in human, rat and mouse skin.

Key words

Epoxide hydratase Glutathione-S-transferase Monooxygenase Lung Cancer 


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  1. Ames, B. N., Sims, P., Grover, P. L.: Epoxides of carcinogenic polycyclic hydrocarbons are frameshift mutagens. Science 176, 47–49 (1972)PubMedCrossRefGoogle Scholar
  2. Bentley, P., Schmassmann, H. U., Sims, P., Oesch, F.: Epoxides derived from various polycyclic hydrocarbons as substrates of homogenous and microsome-bound epoxide hydratase: A general assay and kinetic properties. Europ. J. Biochem. 69, 97–103 (1976)PubMedCrossRefGoogle Scholar
  3. Burke, M. D., Mayer, R. T.: Ethoxyresorufin: Direct fluorimetric assay of a microsomal 0-dealkylation which is preferentially inducible by 3-methylcholanthrene. Drug Met. Disp. 2, 583–588 (1974)Google Scholar
  4. Conney, A. H., Kuntzman, R.: Metabolism of normal body constituents by drug metabolizing enzymes in liver microsomes. Handbook Exp. Pharmacol. 28, 401–421 (1971)Google Scholar
  5. Cookson, M. J., Sims, P., Grover, P. L.: Mutagenicity of Epoxides of polycyclic hydrocarbons correlates with carcinogenicity of parent hydrocarbons. Nature (New Biology) 234, 186–187 (1971)Google Scholar
  6. Daly, J. W., Jerina, D. M., Witkop, B.: Arene oxides and the NIH-shift: The metabolism, toxicity and carcinogenicity of aromatic compounds. Experientia 28, 1129–1149 (1972)PubMedCrossRefGoogle Scholar
  7. DePierre, J. W., Moron, M. S., Johannesen, K. A. M., Ernster, L.: A reliable, sensitive and convenient radioactive assay for Benzpyrene Monooxygenase. Anal. Biochem. 63, 470–484 (1975)PubMedCrossRefGoogle Scholar
  8. Glatt, H. R., Oesch, F., Frigerio, A., Garattini, S.: Epoxides metabolically produced from some known carcinogens and from some clinically used drugs. Differences in mutagenicity. Int. J. Cancer 16, 787–797 (1975)PubMedCrossRefGoogle Scholar
  9. Gram, T. E., Gillette, J. R.: In Fundamentals of Biochemical Pharmacology (Bacg, Z. M., Capek, R., Paoletti, R., Renson, J. (eds.), p. 571. Oxford: Pergamon Press 1971Google Scholar
  10. Grover, P. L., Sims, P.: Interactions of the K-region epoxides of phenanthrene and dibenz-(a, h)anthracene with nucleic acids and histone. Biochem. Pharmacol. 19, 1251–1259 (1970)CrossRefGoogle Scholar
  11. Habig, W. H., Pabst, M. J., Jakoby, W. B.: Glutathione-S-transferases. The first enzymatic step in mercapturic acid formation. J. Biol. Chem. 249, 7130–7139 (1974)PubMedGoogle Scholar
  12. Huberman, E., Sachs, L., Yang, S. K., Gelboin, H. V.: Identification of mutagenic metabolites of benzo(a)pyrene in mammalian cells. Proc. Natl. Acad. Sci. USA 73, 607–611 (1976)PubMedCrossRefGoogle Scholar
  13. Kappus, H., Remmer, H.: Irreversible binding of (14C) Imipramine with rat and human liver microsomes. Biochem. Pharmacol. 24, 1079–1084 (1975)PubMedCrossRefGoogle Scholar
  14. Maleiveille, C., Bartsch, H., Grover, P. L., Sims, P.: Mutagenicity of non-K-region diols and diolepoxides of benz(a)anthracene and benzo(a)pyrene in s.typhimurium TA 100. Biophys. Res. Commun. 66, 693–700 (1975)CrossRefGoogle Scholar
  15. Nebert, D. W.: Fourth European Workshop on Drug Metabolism, University of Mainz, Department of Pharmacology, Sept. 15–20 (1974)Google Scholar
  16. Nebert, D. W., Gelboin, H.V.: Substrate-inducible microsomal aryl hydroxylase in mammalian cell culture. I. Assay and properties of induced enzyme. J. Biol. Chem. 243, 6242–6249 (1968)PubMedGoogle Scholar
  17. Oesch, F., Schmassmann, H. U., Bentley, P.: Specificity of human, rat and mouse skin epoxide hydratase towards K-region epoxides of polycyclic hydrocarbons. Biochem. Pharmacol. 27, 17–20 (1978)PubMedCrossRefGoogle Scholar
  18. Philpot, R. M., Arinc, E., Fouts, J. R.: Reconstitution of the rabbit pulmonary microsomal mixed-function oxidase system from solubilized components. Drug Met. Disp. 3, 118–126 (1975)Google Scholar
  19. Schmassmann, H. U., Glatt, H. R., Oesch, F.: A rapid assay for epoxide hydratase activity with benzo(a)pyrene 4,5-(K-region-)oxide as substrate. Anal. Biochem. 74, 94–104 (1976)PubMedCrossRefGoogle Scholar
  20. Sims, P., Grover, P. L.: Epoxides in polycyclic aromatic hydrocarbon metabolism and carcinogensis. Adv. Cancer Res. 20, 165–274 (1974)PubMedCrossRefGoogle Scholar
  21. Swaisland, A. J., Hewer, A., Pal, K., Keysell, G. R., Booth, J., Grover, P. L., Sims, P.: Polycyclic hydrocarbon epoxides: the involvement of 8,9-dihydro-8,9-dihydroxybenz(a)anthracene-10,11-oxide in reactions with the DNA of benz(a)anthracene-treated hamster embryo cells. FEBS Letters 47, 34–38 (1974)PubMedCrossRefGoogle Scholar
  22. Ullrich, V., Weber, P.: The 0-dealkylation of 7-ethoxycoumarin by liver microsomes. A direct fluorimetric test. Hoppe-Seyler’s Z. physiol. Chem. 353, 1171–1177 (1972)PubMedCrossRefGoogle Scholar
  23. Van Cantfort, J., Manil, L., Gielen, J. E., Glatt, H. R., Oesch, F.: A new assay for glutathione-S-transferase using 3H-benzo(a)pyrene 4,5-oxide as substrate. Inducibility by various chemicals in different rat tissues compared to that of aryl hydrocarbon hydroxylase and epoxide hydratase. Biochem. Pharmacol. (in press 1977)Google Scholar
  24. Wislocky, P. G., Wood, A. W., Chang, R. L., Levin, W., Yagi, H., Hernandez, O., Dansette, P. H., Jerina, D. M., Conney, A. H.: Mutagenicity and cytotoxicity of benz(a)pyrene arene oxides, phenols, quinones and dihydrodiols in bacterial and mammalian cells. Cancer Res. 36, 3350–3357 (1976)Google Scholar

Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • J. Lorenz
    • 1
  • H. Schmassmann
    • 1
  • E. Ohnhaus
    • 2
  • F. Oesch
    • 1
  1. 1.Section on Biochemical PharmacologyInstitute of PharmacologyMainzFederal Republic of Germany
  2. 2.Inselspital BernSwitzerland

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