IMMUNOHISTOCHEMICAL LOCALIZATION OF CYTOCHROME P4501A IN DEVELOPING TURBOT, SCOPHTHALMUS-MAXIMUS

In order to interpret toxic responses of fish embryos and larvae to xe nobiotics, knowledge on biotransformation capacities of fish early lif e stages is important. This study examines by means of immunohistochem istry the expression of cytochrome P4501A (CYP1A), a major inducible e nzyme of xenobiotic metabolism, in the organs of turbot, Scophthalmus maximus, larvae. A polyclonal antiserum (BN-I, Biosense Laboratories), prepared to conserved piscine CYP1A sequences, was used to stain the enzyme in paraffin-embedded tissue sections. Strong immunoreactivity f or CYP1A was obtained in liver parenchymal cells, but hepatic sinusoid eal epithelia also responded positively. Extrahepatically, CYP1A immun oreactivity was found in the kidney tubulus epithelium, in cardiac mus cle cells, in the retina, as well as in endothelia of gill filaments, glomerulum, heart, brain and muscles. The results indicate that the ti ssue distribution patterns of CYP1A in larval turbot are comparable to chose,found in the adults. (C) 1998 Elsevier Science Ltd. All rights reserved.