Sammendrag
The aim of the present study was to investigate the effects of the explosive 2,4,6-trinitrotoluene (TNT) on liver detoxification systems in a model fish species the European eel Anguilla anguilla (Linnaeus, 1758). Eels were exposed in vivo for 6 and 24 h to 0.5, 1 and 2.5mg/L nominal concentration of TNT. CYP1A1, UDPGT and GST genes expression was evaluated by RT-PCR while several enzyme activities such as EROD, MROD, UDPGT, GST and NADPH cyt c reductase were measured by biochemical assays. An in vitro study was also performed only on both CYP1A activities in order to investigated potential interactions of TNT at enzyme level. Any modulation of CYP1A1 gene was observed while on the opposite a significant inhibition of both EROD and MROD activities was observed both in vivo (50-60 %) and in vitro (30 %). UDPGT gene increased in a dose-dependen manner after 6h while any modulation was observed after 24h; the UDPGT enzyme activity tended to increase dose-dependently only at 24h. GST gene increased as well in a dose dependent manner but only after 24h while significant increases of GST activity were observed both at 6 and 24 h but only at the highest concentration. An increase of NADPH reductase activity was observed at 24h. Our results seem to indicate a clear inhibitory action on CYP1A-dependent catalytic activities by TNT and a clear involvement of phase II (UGST and UDPGT) enzymes as well as NADPH cyt reductase in TNT metabolism in eels.
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