Excited states of oxygen in biology: Their possible involvement in cytochrome P450 linked oxidations as well as in the induction of the P450 system by many diverse compounds

Paine, Alan J.

doi:10.1016/0006-2952(78)90023-0

Cited by 48 publications

(3 citation statements)

References 107 publications

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“…Conceivably, these peroxides or their secondary metabolites could be involved in the induction process either directly or indirectly (Paine, 1978) (Fig. 5, Scheme 3).…”

Section: Mechanisms Of Pb Inductionmentioning

confidence: 99%

Phenobarbital induction of cytochrome P-450 gene expression

Waxman

Azaroff

1992

Biochemical Journal

496

265

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“…Conceivably, these peroxides or their secondary metabolites could be involved in the induction process either directly or indirectly (Paine, 1978) (Fig. 5, Scheme 3).…”

Section: Mechanisms Of Pb Inductionmentioning

confidence: 99%

Phenobarbital induction of cytochrome P-450 gene expression

Waxman

Azaroff

1992

Biochemical Journal

496

265

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“…During the course of aerobic metabolic reactions a considerable amount of reactive oxygen species such as superoxide anions (i®2) and hydrogen peroxide (H2O2) are generated [1][2][3] . H202 and 02 further undergo a variety of chain reactions and produce free radicals such as 0H' and HO2.…”

mentioning

confidence: 99%

Effect of Ascorbic Acid on Antioxidant Defense Systems and Lipid Peroxidation in Guinea Pig

Koul

Khanduja

Koul

et al. 1989

J. Clin. Biochem. Nutr.

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In view of the antioxidant properties of ascorbic acid (AA), effects of inadequate and excessive doses of AA on hepatic and pulmonary antioxidant enzymes and NADPH-dependent lipid peroxidation were investigated in the present study. Male guinea pigs, dosed daily with 0.2 mg AA/100 g b wt (inadequate) or 50 mg AA/100 g b wt (excessive) for 8 weeks, demonstrated no difference in body growth, liver and lung weights, and post-10,000 X g supernatant protein contents as compared with the control group, which was daily fed with 2 mg AA/ 100 g b wt. Inadequacy of AA decreased the hepatic and pulmonary contents of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), but it significantly increased glutathione reductase (GR) activity (p <0.005) in lung. However, levels of hepatic and pulmonary NADPH-dependent lipid peroxidation remained unaltered when the supply of AA was inadequate. Excessive doses of AA did not influence any pulmonary antioxidant enzyme, level of NADPHdependent lipid peroxidation and content of reduced glutathione (GSH), but increased the hepatic GSH-Px and GR activities. Hepatic SOD activity showed a significant decrease (p <0.01), whereas NADPHdependent lipid peroxidation and GSH contents remained unchanged. It appears that the changes in antioxidant enzymes may be a nonspecific response to AA or these changes may not be sufficient to bring about any shift in the levels of NADPH-dependent lipid peroxidation in the presence of unaltered GSH contents or other biomolecules which may act as antioxidants or free radical scavengers in the cell system.

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“…

In hepatic cells, oxygen free radicals, among others, .occurs during biotransformations of xenobiotics where P-450 cytochrome linked oxidations are involved (Paine, 1978) and especially with compounds presenting one or more aromatic rings in their structure. The superoxide anion radical, formed early during this enzymatic process, is rapidly converted into the highly reactive hydroxyl radical which promotes the peroxidation of polyunsaturated fatty acids in organelles and plasma membranes.

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mentioning

confidence: 99%