The assessment of vitellogenin as a biomarker of exposure to estrogenic compounds in two Australian perciformes

Vitellogenin (Vtg) is a yolk protein precursor that has been identified as a sensitive biomarker for exposure to estrogenic compounds. We evaluated specific monoclonal and polyclonal antibodies for reactivity with plasma Vtg from two Australian Perciformes, the tropical barramundi (Lates calcanifer) and the temperate black brearn (Acanthopagrus butcheri). Blood plasma from 17p-estradiol exposed (EA male barramundi (20 mg kg-1) and male black bream (2.5-5.0 mg kg-') were sent to Biosense Laboratories (Norway) for cross-reactivity testing using their extensive anti-Vtg antibody selection. Indirect ELISA results determined barramundi plasma displayed the highest binding affinities to ND-3G2 (monoclonal-Mab) and PO-1 (polyclonal-Pab). Black brearn was most cross-reactive with ND-1C8 (Mab) and PC2 (Pab). Next, plasma was assessed for Vtg induction in E2-closed (5 mg kg-1), hatchery-reared barramundi and black bream, versus a non-injected control group. Vtg production was assessed by Western blot and indirect ELISA using ND-3G2 and ND-1C8 Mabs, respectively. A prominent band was identified in the range of 100-200 kDa for all female black bream and for all E2-treated barramundi and black bream, males, which was confirmed as Vtg by Western blot. Indirect ELISA results for barramundi demonstrated highly significant differences in E2-closed fish as compared to control fish (Student t, P < 0.001). E2 male black bream were significantly different than control males (Student t, P < 0.001) and control and E2 females displayed highly significant differences (Student t, P < 0.001). These results indicate that exposure to 17p-estradiol induces significant Vtg production in males of the two Australian Perciformes, with potential use as a biomarker for exposure to estrogenic compounds. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.