Ring oxidation of 6-nitrobenzo (a) pyrene by female mouse liver.
6-Nitrobenzo (a) pyrene (6-NBaP) is an environmental contaminant. In bacterial mutagenesis assays, 6-NBaP requires rat liver S9 enzymes for its activity. Chemical characterization of metabolites of 6-NBaP produced by male rat liver microsomes showed them to be ring-hydroxylated (both mono- and dihydroxy) derivatives. Thus, metabolic activation of 6-NBaP may occur via ring oxidation. It has been shown by others that when injected intraperitoneally into newborn mice, 6-NBaP was carcinogenic to male, but not to female, mouse liver. The nitro-hydrocarbon was not carcinogenic to the lungs of either sex. We have examined the metabolism of 6-NBaP by the liver of a non-susceptible female mouse and observed the formation of ring-hydroxylated metabolites of 6-NBaP. In view of this observation, we suggest that ring hydroxylation alone may not be sufficient in explaining the carcinogenicity of 6-NBaP in male and not in female mice.
Raha
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C
Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68105.
Williamson
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D
Hart-Anstey
M
M
Maiefski
T
T
Stohs
S J
SJ
Bresnick
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E
D000107:Acetylation; D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D013347:Subcellular Fractions / Q000378:metabolism
D001580:Benzopyrenes; C034699:6-nitrobenzo(a)pyrene