In vitro exposure of Nile tilapia (Oreochromis niloticus) testis to estrogenic endocrine disrupting chemicals: mRNA expression of genes encoding steroidogenic enzymes

作者：Ribeiro Claudia; Urbatzka Ralph; Castro L Filipe C; Carrola Joao; Fontainhas Fernandes Antonio; Monteiro Rogerio A F; Rocha Eduardo; Rocha Maria J^*

来源：Toxicology Mechanisms and Methods, 2012, 22(1): 47-53.

DOI：10.3109/15376516.2011.593053

• EDCs
• testis
• steroidogenesis
• environmental mixtures
• 17 beta-HSD
• estrogens

Many environmental pollutants can exert adverse effects on exposed organisms, including fish, leading to disruption of the endocrine system. Enzymes involved in the sex steroid biosynthesis are potential targets for the toxic action of pollutants. In this context, we investigated the hypothesis that selected estrogenic chemicals-the pharmaceutical estrogen ethinylestradiol (EE2), the phytoestrogen genistein (GEN), and the industrial compound bisphenol A (BPA)-may cause endocrine disruption by directly disturbing steps of fish steroidogenic pathways. We studied the mRNA expression of eight selected genes encoding steroidogenic enzymes (11 beta-HSD2, 20 beta-HSD, 3 beta-HSD1, 17 beta-HSD1, 17 beta-HSD8, 17 beta-HSD12, CYP19a, CYP19b) by quantitative real-time PCR. Testis slices from adult specimens of the model fish Nile tilapia were exposed in vitro for 3 and 8 h either to individual or to mixture solutions of EE2 (100 ng/L), GEN (200 ng/L), and BPA (10 mu g/L); all at the peak concentrations observed in the Douro River estuary (Portugal). Our data revealed that only the mixture of the tested chemicals directly induced the expression of 11 beta-HSD2, 17 beta-HSD1, and 17 beta-HSD12, after 8 h, whereas no effect was seen for chemicals tested individually. The gene expression pattern agrees with the concept of dose addition for environmental mixtures, and for the first time an interference of estrogenic EDCs is reported for 17 beta-HSD1 and 17 beta-HSD12.%26lt;/.

• 出版日期2012-1