Inhibition of arylhydrocarbon hydroxylase and cytochrome P-450 by 20-methylcholanthrene and phenobarbital in guinea pig on excessive doses of ascorbic acid.
Treatment of guinea pigs on adequate ascorbic acid (AA) with 20-methylcholanthrene (MCA) and phenobarbital (PB) significantly increased hepatic arylhydrocarbon hydroxylase (AHH), cytochrome P-450 and cytochrome-b5 activities. In lungs, only MCA treatment significantly enhanced the activities of AHH, cytochrome P-450 and cytochrome b5. In animals on excessive doses of AA, there was inhibition of hepatic AHH, cytochrome P-450 and cytochrome b5 levels by treatment with these xenobiotics. Also, inhibition was observed in pulmonary AHH and cytochrome P-450 levels. The relevance of these observations in excessive AA-fed guinea pigs to carcinogenesis requires further extensive investigations.
Khanduja
K L
KL
Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Kapur
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Koul
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Majid
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Koul
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Sharma
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D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D065607:Cytochrome P-450 Enzyme Inhibitors; D015786:Cytochromes b5 / Q000378:metabolism; D006168:Guinea Pigs; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D010634:Phenobarbital
D065607:Cytochrome P-450 Enzyme Inhibitors; D008748:Methylcholanthrene; D015786:Cytochromes b5; D001189:Aryl Hydrocarbon Hydroxylases; D001205:Ascorbic Acid; D010634:Phenobarbital