112 Abstracts

in the food chain may be a sensitive indicator of the extent of the effect of chemical pollutants in the ocean environment.

Hepatic Microsomal Cytochromes P-450 from BNF-treated Perch. LARS FQRLIN,* TOMMY ANDERSSON,* ANDERS GOKS~OYRt & YUSHENG ZHANG.*:~ *Department of Zoophysiology, University of G6teborg, Box 25059, S-40031 G6teborg, Sweden; tDepartment of Biochemistry, University of Bergen, N-5000 Bergen, Norway & ~Third Institute of Oceanography, State Oceanic Administration, Box 70, Xiamen, Fujian, The People's Republic of China.

Intraperitoneal injection of perch (Percafluviatilis) from the Swedish east coast with #-naphthoflavone (BNF) (50mg/kg body weight) resulted in 5-15-fold induction of hepatic microsomal cytochrome P-450- dependent ethoxyresorufin-O-deethylase (EROD) activity, whereas no new protein bands appeared in the P-450 region as judged by SDS-PAGE. In immunoblot analysis, the polyclonal IgG to BNF-inducible P-450c from Atlantic cod (Gadus morhua) cross-reacted with a microsomal protein band from both BNF-treated and untreated perch. This antibody strongly inhibited the microsomal EROD activities from both treated and untreated fish. These results indicate that feral perch from the Swedish east coast (Sea of Bothnia) may well be environmentally induced. Separation and purification of hepatic microsomal P-450s from BNF-treated perch by solubilisation of microsomes with CHAPS, phenyl-sepharose CL-4B and DEAE-sepharose chromatographies resulted in four partly purified P-450 containing fractions. The major fraction contains P-450 with an approxi- mate m.w. of 58000 Dalton and to a minor extent P-450 with an approximate m.w. of 54000 Dalton, as judged by SDS-PAGE. The three other fractions seemed to contain P-450s with an approximate m.w. of 54 000 and/or 48 000-49 000 Dalton. The P-450s from the major fractions were separated by FLPC chromatography using a Mono-Q anion-exchange column. The IgG to cod P-450c cross-reacted only with the high m.w. perch P-450 (58000). The similarities in m.w. and immunological properties between the high m.w. perch P-450 and cod P-450c may indicate that the major PAH-inducible P-450 isoenzyme from perch liver microsomes were isolated in the present study.

Purification and Characterization of Cytochromes P-450 from 3-MC-induced Plaice. FIONA CAMPBELL,* DANNY BURKE* & STEPHEN GEORGE.~ *Department of Pharmacology, Aberdeen University, Aberdeen, Great Britain & t NERC Unit of Aquatic Biochemistry, University of Stirling, Stirling, Great Britain.

Abstracts 113

Multiple forms of cytochrome P-450 were induced by intraperitoneal injection of plaice with 3-methylcholanthrene (3-MC; 100mg/kg). The induction response was greatest in fish collected in the summer and there was no induction of constitutive P-450s in mature female fish. Two cytochromes P-450 of approximately 50-53 kDa were purified from CHAPS-solubilized microsomes by hydrophobic interaction and ion-exchange chromatography and preparative electrophoresis. The physical and immunological properties of the purified enzymes were presented.

Biochemical and Physiological Responses in Gobiidae Experimentally Exposed to PCBs. CRISTINA FOSSI, CLAUDIO LEONZIO & SILVANO FOCARDI. Dipartimento di Biologia Ambientale, Universita di Siena, via delle Cerchia 3, 53100 Siena, Italy.

Gobiidae is a family of fish found in polluted and unstable marine environments. Thus, biochemical and physiological responses studied in two species experimentally exposed to PCBs provide an excellent opportunity to evaluate the functioning of the detoxication system (MFO) in the adaptation to pollution. In this study, specimens of Gobius niger and Zosterisessor ophiocephalus were collected in a harbour and in a lagoon of the Tyrrhenian Sea. Specimens of each group were placed in aquaria and, after 20 days of acclimation, the control fish were analysed, then Aroclor 1260 (10 #g/litre) was added to the water. After 6, 12 and 20 days of exposure we detected benzo[a]pyrene monooxygenase (BPMO), NADPH- and NADH-cyto- chrome c reductase (NADPH- and NADH-CYTCRED) and NADH- ferricyanide reductase (NADH-FERRIRED) activities in the liver of the two species. Electrophoretic analysis and measurement of somatic liver index and PCB content in muscle were also performed. The same tests were carried out on the fish in natural conditions. Analysis revealed that the PCB content and the MFO activity were higher in G. niger than in Z. ophiocephalus. In the experimental treatment with PCBs the two species present different responses for MFO activity and for PCB accumulation in muscle. In the last experimental period (20 days) the PCB levels in muscle were four times higher in G. niger than in Z. ophiocephalus; the induction of BPMO, NADPH-CYTCRED, NADH-CYTCRED and NADH- F E R R I R E D was also higher in G. niger. Interspecific differences in the response toward the same chemical stress due to physiological, genetic or adaptive differences could explain this phenomena.

Xenobiotic Metabolizing Enzymes in Two Species of Benthic Fish showing Different Prevalences of Hepatic Neoplasms in Contaminated Areas.