Hepatic microsomal mono-oxygenase activity and P450IA mRNA in North Sea dab Limanda limanda from contaminated sites

Abstract

Mature pre-spawning female dab Limanda limanda were sampled during the Bremerhaven Workshop from stations in the southern North Sea along a transect heading approxin~ately NW from the Elbe estuary (the 'German Bight Transect') and around an abandoned drilling s~t e .Hepatic rnicrosomal mono-oxygenase activity as shown by ethoxyresorufin 0-deethylase (EROD) and cyanoethoxycoumarin 0-deethylase (CN-ECOD) declined with increasing distance offshore, but rose slightly a t the outermost station on the Dogger Bank. Microsomal P4501A1 mRNA, detected with a new synthetic oligonucleotide probe, followed the same trend. Activities of EROD and CN-ECOD and concentrations of P4501A1 mRNA were well correlated with the major chlorobiphenyl residues measured in dab and with hydrocarbon concentrations in sedlments at these stations. Dab sampled from the drilling site had hepatic EROD and CN-ECOD activ~ty and P4501A1 mRNA contents similar to those in fish from the offshore German Bight stations.

Mutual in vivo interactions between benzo[a]pyrene and tributyltin in brook trout (Salvelinus fontinalis)

“…However, the in vivo effects of TBT on CN‐ECOD activity have not been previously investigated. Furthermore, CN‐ECOD activity in fish has only be measured in a very limited number of laboratory [33] and field [34,35] studies. From those studies, however, it emerged as a more sensitive indicator of induction than EROD.…”

Antioxidant enzymes in liver of dab Limanda limanda from the North Sea

“…In the case of SOD, a distinct U-shaped profile was apparent through Stns 1 to 9. An increase in activity at Stn 9 compared to Stn 8 was also observed for 'hydrocarbon-inducible' cytochrome P4501A1 activity ) (Renton & Addison 1992), and correlations between elevated hepatic SOD and aryl hydrocarbon hydroxylase (indicative of P4501A1) activities have been seen in field studies of Leiostomus xanthurus (Roberts et al 1987). Several other vanables also indicated increased biological effect on dab towards and/or at the Dogger Bank, e.g.…”

“…Mature female fish of similar size were used, ranging in length from 21.7 f 0.6 cm (Stn 9) to 24.2 f 0.6 cm (Stn 1) (mean f SEM). Fish were sacrificed as described by Renton & Addison (1992) and the livers dissected out, weighed and either used immediately, or stored frozen at -70 'C prior to analysis.…”

Detection of cytochrome P450 1A1 in North Sea dab liver and kidney

“…Samples were generally obtained after dissection of the fish on board ship, frozen in liquid nitrogen, and transferred to the laboratory on shore (Alfred-Wegener-Institut, Bremerhaven) for processing of samples. Liver post-mitochondrial supernatants were obtained after 12 000 X g centrifugation of the homogenized tissue ) and microsomes were prepared from a 100000 X g pellet, as described elsewhere (Renton & Addison 1992). Head kidney microsomes and trunk kidney post-mitochondrial supernatants were prepared as described previously (Pesonen & Anderson 1987).…”

“…In fish, these activities are believed to represent the catalytic activity of a single CYP form, CYP 1Al or P450 l A l , a member of the CYP 1A subfamily, being responsive to organic contaminants by gene activation. The induction response can also be studied at other levels, such as with nucleotide probes for measuring mRNA levels (Renton & Addison 1992), or with antibody probes for measuring the translated protein product (reviewed in Gokseryr & Fijrlin 1992).…”