Induction of liver EROD and erythrocytic nuclear abnormalities by cyclophosphamide and PAHs in Anguilla anguilla L.

The induction of liver ethoxyresorufin O-deethylase (EROD) activity and erythrocytic nuclear abnormalities (NA) after treatment with two different polycyclic aromatic hydrocarbons (PAHs) and cyclophosphamide (CP) was investigated in the eel Anguilla anguilla L. EROD activity significantly increases either 3 days after one single i.p. injection or 6 days after two i.p. injections (on days 0 and 3) of 4 mg/kg beta-naphthoflavone (BNF). EROD activity was determined after different lengths of exposure to 4 mg/kg BNF (i.p. injection). The results indicated significant increases from 8-h to 12-day exposure, with a maximum increase at 4 days and a decline between 4 and 12 days. The induction of liver EROD activity and erythrocytic NA was studied, 3 days after one 14.7-mumol/kg treatment (i.p. injection) with BNF, benzo[a]pyrene (BaP), and CP, in three three different groups of eels. The EROD activity significantly increases after BNF and BaP treatment, whereas the erythrocytic NA frequency was kept constant; however, CP induces a significant increase in the erythrocytic NA frequency, but it does not induce a significant increase in liver EROD activity. The sensitivity of A. anguilla liver EROD assay was assessed 3 days after one i.p. injection of BNF (0.0, 0.03, 0.06, 0.125, 0.25, 0.5, 1.0, 2.0, and 4.0 mg/kg). This species exhibits a dose response to BNF at the concentration range 0-4 mg/kg. The NOEL is between 0.125 and 0.25 mg/kg. The eels 3-day exposure to water containing BNF (0.0, 0.1, 0.3, 0.9, and 2.7 microM) induced a significant increase in liver EROD activity, specifically in concentrations of 0.9 and 2.7 microM. The NOEC for the eels external exposure to BNF is between 0.3 and 0.9 microM.