Immunochemical characterization of hepatic cytochrome P450 isozymes in the channel catfish: assessment of sexual, developmental and treatment-related effects.
The profiles of immunoreactive proteins recognized by antibodies raised against purified trout P-450 isoforms (CYP1A1, CYP2M1 and CYP2K1) were examined in channel catfish liver by Western blot analysis. Gender differences in basal expression of these isoforms, as well as responses to known inducers of mammalian isoforms (ethanol, beta-naphthoflavone and clofibric acid) and early life stage (3 and 6 months) profiles are described. Two similar protein bands were detected by Western blotting in mature untreated catfish with CYP2K1 and CYP2M1 antibodies. A third band is detected by anti-2K1 in fish treated with beta-naphthoflavone; this band was verified as CYP1A, with about twice the level of expression in males versus females. No difference between sexes was seen in the expression of the 51-kDa CYP2-reactive bands; however, a significant difference (female > male) was seen in the lower molecular weight CYP2 band (47-kDa). Ethanol treatment caused a dose-dependent decrease in the 47-kDa CYP2-reactive isoforms but no change in the 51-kDa band. Clofibric acid treatment caused an increase in both the 51-kDa CYP2 protein as well as in liver somatic index. Age-dependent changes in isoform expression were also detected in CYP2-reactive forms, with a novel protein (53-kDa) detected in 3-month-old fish. The results from this study provide insight into the regulation of constitutive catfish CYP isoforms and prepares a foundation for further examination of the biotransformation capabilities of an important aquatic species.
Perkins
E J
EJ
Environmental Toxicology Research Program/RIPS, Department of Pharmacology, University of Mississippi 38677, USA.
Schlenk
D
D
D000818:Animals; D000918:Antibody Specificity; D015153:Blotting, Western; D002995:Clofibric Acid / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D004790:Enzyme Induction; D000431:Ethanol / Q000494:pharmacology; D007059:Ictaluridae; D007527:Isoenzymes / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D012737:Sex Factors; D019324:beta-Naphthoflavone / Q000494:pharmacology