Role of cytochrome P-450 in ochratoxin A-stimulated lipid peroxidation.

The role of cytochrome P-450 in the stimulation of lipid peroxidation by the nephrotoxic mycotoxin ochratoxin A has been investigated. Ochratoxin A was previously shown to markedly stimulate lipid peroxidation in a reconstituted system consisting of phospholipid vesicles, NADPH-cytochrome P-450 reductase, Fe3+, ethylenediaminetetraacetic acid (EDTA), and reduced nicotinamide adenine dinucleotide phosphate (NADPH). We now show that purified cytochrome P-450IIB1 could effectively replace EDTA in stimulating lipid peroxidation suggesting that it could mediate the transfer of electrons from NADPH to Fe3+. Cobalt protoporphyrin is known to cause an extensive and long-lasting depletion of hepatic cytochrome P-450 in rats, and it has been used to evaluate the role of hepatic cytochrome P-450 in xenobiotic metabolism and toxicity. We have observed that microsomes isolated from livers of cobalt protoporphyrin-pretreated rats underwent ochratoxin A-dependent lipid peroxidation much more slowly than control microsomes. Also, the level of ethane exhaled (an index of in vivo lipid peroxidation) on ochratoxin A administration was much lower in cobalt protoporphyrin-pretreated rats than in control rats. Taken together, these results provide evidence for the stimulatory role of cytochrome P-450 in ochratoxin A-induced lipid peroxidation in a reconstituted system and strongly implicate its role in microsomal and in vivo ochratoxin A-induced lipid peroxidation.

[1]  B. Hasinoff,et al.  Mechanism of ochratoxin A stimulated lipid peroxidation. , 1990, Biochemical pharmacology.

[2]  S. Schenker,et al.  A model of cytochrome P-450-centered hepatic dysfunction in drug metabolism induced by cobalt-protoporphyrin administration. , 1989, Biochemical pharmacology.

[3]  D. Jollow,et al.  Effect of cobalt protoporphyrin on hepatic drug-metabolizing enzymes. Specificity for cytochrome P-450. , 1989, Biochemical pharmacology.

[4]  H. Bartsch,et al.  Lipid peroxidation as a possible cause of ochratoxin A toxicity. , 1988, Biochemical pharmacology.

[5]  S. Aust,et al.  Reconstituted microsomal lipid peroxidation: ADP-Fe3+-dependent peroxidation of phospholipid vesicles containing NADPH-cytochrome P450 reductase and cytochrome P450. , 1988, Free radical biology & medicine.

[6]  C. Lieber,et al.  Purification of NADPH:cytochrome c (cytochrome P-450) reductase from hamster liver microsomes by detergent extraction and affinity chromatography. , 1987, Analytical biochemistry.

[7]  A. Bendele,et al.  Ochratoxin A carcinogenesis in the (C57BL/6J X C3H)F1 mouse. , 1985, Journal of the National Cancer Institute.

[8]  G. Drummond,et al.  The cytochrome P-450-depleted animal: an experimental model for in vivo studies in chemical biology. , 1982, Proceedings of the National Academy of Sciences of the United States of America.

[9]  L. Ernster,et al.  MICROSOMAL LIPID PEROXIDATION: MECHANISM AND SOME BIOMEDICAL IMPLICATIONS , 1982 .

[10]  P. R. Miles,et al.  Inhibition of hepatic microsomal lipid peroxidation by drug substrates without drug metabolism. , 1980, Biochemical pharmacology.

[11]  P. O'Brien,et al.  Differential effects of antioxidants, steroids and other compounds on benzo(a)pyrene 3-hydroxylase activity in various tissues of rat. , 1979, British Journal of Cancer.

[12]  S. Aust,et al.  NADPH-dependent lipid peroxidation catalyzed by purified NADPH-cytochrome c reductase from rat liver microsomes , 1972 .

[13]  T. Omura,et al.  THE CARBON MONOXIDE-BINDING PIGMENT OF LIVER MICROSOMES. II. SOLUBILIZATION, PURIFICATION, AND PROPERTIES. , 1964, The Journal of biological chemistry.

[14]  L. Ernster,et al.  Evidence for the involvement of iron in the ADP-activated peroxidation of lipids in microsomes and mitochondria. , 1964, Biochemical and biophysical research communications.

[15]  S. Orrenius,et al.  Inhibition of the TPNH-linked lipid peroxidation of liver microsomes by drugs undergoing oxidative demethylation. , 1964, Biochemical and biophysical research communications.

[16]  W. J. Dyer,et al.  A rapid method of total lipid extraction and purification. , 1959, Canadian journal of biochemistry and physiology.

[17]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[18]  E. Jellinek,et al.  THE OXYGEN AND CARBON DIOXIDE CONTENT OF THE ARTERIAL AND VENOUS BLOOD OF NORMAL SUBJECTS , 1937 .