Comparison of liver mixed-function oxygenase and antioxidant enzymes in vertebrates.
We performed a comparative analysis of cytochrome P450, cytochrome b5, 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 b5 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 b5 concentration to that of P450. Most species showed cytochrome b5 sensitivity to oxygen. Thus, the use of sodium dithionate as a reducer, rather than NADPH, may be preferential in b5 determinations.
Rocha-e-Silva
Thomaz A A
TA
Department of Physiological Sciences/Federal University of São Carlos, Rod. Washington Luís, km 235, 13650-905 São Carlos, São Paulo, Brazil.
Rossa
Marcelo M
MM
Rantin
Francisco T
FT
Matsumura-Tundisi
Takako
T
Tundisi
Jose G
JG
Degterev
Igor A
IA
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001001:Anura; D005260:Female; D005399:Fishes; D008099:Liver / Q000201:enzymology*; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors; D013045:Species Specificity
D000975:Antioxidants; D006899:Mixed Function Oxygenases