Effects of endocrine disruptors on nervous system related gene expression: Comprehensive analysis of Medaka fish

Abstract

A number of environmental compounds have been reported to interact with the endocrine system and are thus referred to as endocrine disrupting chemicals. Although it is well known that estrogenic endocrine disrupting compounds stimulate the abnormal expression of the vitellogenin gene in the livers of various aquatic male vertebrates, leading to hepatic production of the vitellogenin protein, there are only few reports investigating the effects of estrogenic pollutants on function related to the nervous system. In the present study, male medaka was exposed to five estrogenic compounds: 17β-Estradiol, 17α-ethinylestradiol, 4-nonylphenol, 4-tert-octylphenol and bisphenol A. Gene profiles were then obtained using a medaka DNA microarray where probes consisted of genes derived from EST libraries prepared from the liver, ovary and brain. To evaluate the effects of these compounds on gene expression related to the nervous system, we estimated comprehensive impact values using the Pearson correlation coefficient by comparing the gene expression profiles of untreated males versus treated males. Results indicated that 17β-Estradiol and 17α-ethinylestradiol exhibited a strong impact on gene expression derived from both the liver and ovary library, whereas some of the 17α- ethinylestradiol treatments disrupted genes derived from the brain library and also nervous system specific gene expression. It is suggested that neuronal damage could occur in medaka following exposure to endocrine disrupting compounds. © 2009 Springer Netherlands.