Biomaterial Database

Oxidative biotransformation of benzo(a)pyrene by human lung microsomal fractions prepared from surgical specimens. 1979

Z Sípal, and T Ahlenius, and A Bergstrand, and L Rodriquez, and S W Jakobsson

1. Microsomal fractions were prepared from 15--50 g specimens of human lung tissue (mostly alveolar) obtained at surgical resections of 13 middle-aged male patients suffering from different pulmonary tumours. Marker enzyme assays indicated that the frations contained about 25% of the endoplasmic reticulum of the homogenate and about 10% of its mitochondrial membranes. 2. The content of cytochrome b5 corresponded to that of rodent lung microsomes, whereas the apparent content of cytochrom P-450 was much lower. 3. The extent of benzo(a)pyrene metabolism varied 13-fold between individuals in the group and was not detectable in about 40% of the cases. 4. The dihydrodiols as % of total metabolites formed was higher than in laboratory animals, the 7,8-dihydrodiol in most cases amounting to more than 40% of total dihydrodiols. 5. The apparent rate of hydroxylation was stimulated by 1 mM 2-diethylaminothyl 2,2-diphenylvalerate and by 1 mM 1,2-oxy-3,3,3-trichloropropane, but inhibited moderately by 0.1 mM metyrapone and extensively by 0.05 mM 7,8-benzoflavone. 6. Ethoxyresorufin deethylation qualitatively paralleled benzo(a)pyrene hydroxylation among individuals.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D008175	Lung Neoplasms	Tumors or cancer of the LUNG.	Cancer of Lung,Lung Cancer,Pulmonary Cancer,Pulmonary Neoplasms,Cancer of the Lung,Neoplasms, Lung,Neoplasms, Pulmonary,Cancer, Lung,Cancer, Pulmonary,Cancers, Lung,Cancers, Pulmonary,Lung Cancers,Lung Neoplasm,Neoplasm, Lung,Neoplasm, Pulmonary,Pulmonary Cancers,Pulmonary Neoplasm
D008297	Male		Males
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001579	Benzopyrene Hydroxylase	A drug-metabolizing, cytochrome P-448 (P-450) enzyme which catalyzes the hydroxylation of benzopyrene to 3-hydroxybenzopyrene in the presence of reduced flavoprotein and molecular oxygen. Also acts on certain anthracene derivatives. An aspect of EC 1.14.14.1.	Benzopyrene-3-Monooxygenase,Benzo(a)pyrene Hydroxylase,Benzo(a)pyrene Monooxygenase,Benzopyrene 3 Monooxygenase,Hydroxylase, Benzopyrene
D001580	Benzopyrenes	A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it.	Benzpyrene
D001711	Biotransformation	The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In