Comparison of liver mixed-function oxygenase and antioxidant enzymes in vertebrates

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology Vol. 137; no. 2; pp. 155 - 165
• Main Authors: Rocha-e-Silva, Thomaz A.A., Rossa, Marcelo M., Rantin, Francisco T., Matsumura-Tundisi, Takako, Tundisi, Jose G., Degterev, Igor A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-02-2004
• Subjects: Amphibians; Animals; Antioxidant enzymes; Antioxidants - metabolism; Anura; Cytochromes; Female; Fish; Fishes; Hepato-somatic index; Liver - enzymology; Male; Microsomal protein index; Mixed Function Oxygenases - metabolism; Mixed-function oxidase; Rat; Rats; Rats, Wistar; Sex Factors; Species Specificity; Rat; Antioxidant enzymes; MFO, mixed-function oxidase; Amphibians; SOD, superoxide dismutase; Microsomal protein index; EROD, 7-ethoxyresorufin deethylase; Hepato-somatic index; BM, body mass; CAT, catalase; HSI, hepato-somatic index; Fish; Cytochromes; MPI. microsomal protein index; NCCR, NADPH-dependent cytochrome c (P450) reductase; Mixed-function oxidase
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cca.2004.01.007

We performed a comparative analysis of cytochrome P450, cytochrome
b
5, MFO associated enzymes and cytosolic antioxidant enzymes in hepatic microsomes and cytosolic fractions prepared from five animal species representing three vertebrate classes living in tropical conditions (Brazil). The data obtained show that rats have higher hepato-somatic index, specific cytochrome
b
5 concentration, and NADPH-dependent cytochrome
c (P450) activity compared to ectothermic species, SOD activity similar to those in amphibians, and specific concentration of cytochrome P450 and catalase activity lower than in a toad, but higher than in fishes and a frog. Our data indicate that tropical fishes may have reduced xenobiotic-metabolizing ability compared to the rat and amphibians. In contrast to fish and rat, amphibians have a low ratio (<0.5) of cytochrome
b
5 concentration to that of P450. Most species showed cytochrome
b
5 sensitivity to oxygen. Thus, the use of sodium dithionate as a reducer, rather than NADPH, may be preferential in
b
5 determinations.