A biomarker approach to endocrine disruption in flounder—estrogen receptors, hepatocyte proliferation, and sperm motility

Three different physiological parameters were assessed to determine their potential for serving as biomarkers to predict abnormally elevated vitellogenin (VTG) production in male and immature flounder. Whereas abnormally elevated mean VTG plasma concentrations clearly distinguished the Mersey and Dee flounder studied, the results showed no significant differences in estrogen receptor binding capacity or binding affinity between the two groups. Hepatocyte proliferation was not found to be a “biomarker of effect” that could specifically be used to assess an increase in VTG-related proliferation. Nevertheless, immunohistochemical staining for proliferating cell nuclear antigen did show a significantly higher proliferative activity in the livers of Mersey flounder than that in Dee flounder. Sperm motility also was not found to be a biomarker of effect linked to an abnormal elevation of VTG plasma concentration. The results (higher sperm quality in terms of motility in Mersey flounder) were unexpected but interesting.