Histopathological and proteomic analysis of hepatic tissue from adult male zebrafish exposed to 17β-estradiol

17β-Estradiol (E2) is known to contribute significantly a large extent to the estrogenicity in aquatic system. In the present study, two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MALDI–TOF–TOF MS), combined with histopathological analysis, was used to screen hepatic responses in adult male zebrafish. Eight proteins were found to be up-regulated more than 2-fold, whereas five protein spots were down-regulated more than 2-fold after 1 nM E2 treatment for 14 days, which had caused histological effects in zebrafish livers. These differentially expressed proteins accounted for a variety of cellular biological processes, such as response to oxidative stress, cell surface receptor-linked signal transduction, oxidation–reduction and cellular calcium ion homeostasis. The results demonstrated that E2 comprehensively influenced a variety of cellular and biological processes in zebrafish. Moreover, the proteomic responses elicited in zebrafish allow us to better understand the underlying mechanisms of endocrine-disrupting chemicals (EDCs)-induced toxicity fully.