SUITABILITY OF THE RUFFE (GYMNOCEPHALUS-CERNUA [L]) FOR INVESTIGATIONS ON ACTIVITY OF HEPATIC-ENZYMES INDUCED BY XENOBIOTICS

Activity measurements of enzymes catalyzing (i) the oxidation of xenob iotics (phase I) and (ii) the conjugation of metabolites produced in p hase I (phase II) were carried out in ruffe to test its suitability fo r biological monitoring. Ruffe typically lives in the lower regions of rivers and in estuaries where monitoring is of particular interest fo r estimating the amount of pollutants introduced into the sea. The flo under, already examined for this purpose, is used as reference organis m. In ruffe, the enzymatic activity (7-ethoxycoumarin-O-deethylase (EC OD) and 7-ethoxyresorufin-O-deethylase (EROD)) increased with the cont amination of the river toward Hamburg whereas in flounder it did not. The absence of a correlation between induction of the enzymatic activi ty in flounder and environmental contamination is attributed to the hi gher readiness of the flounder to migrate. Therefore, mixed function o xygenase activity found in flounders may not represent the inducing ca pacity of the local concentrations of xenobiotics. Since ECOD activity in ruffe was 5 to 20 times higher compared to the flounder, histopath ological findings of investigations of the liver tissue were considere d, Destruction or pathological changes of the endoplasmatic reticulum (where ECOD and EROD are located) is often reported in flounder but no t in the ruffe, which may influence the expression of some enzymatic a ctivities. The enzymatic activity of the phase II enzyme glutatione-S- transferase, which is considered to have a protective function in the cell against damages, caused by reactive metabolites, was more induced in ruffe than in flounder. Thus the ruffe may be less subjected to ce ll injury. (C) 1995 Academic Press, Inc.