Hormonal effects of tetrabromobisphenol A using a combination of in vitro and in vivo assays

The aim of this study was to investigate the hormonal effects of tetabromobisphenol A (TBBPA) in vitro on recombinant yeasts and in vivo on mosquitofish (Gambusia affinis). The in vitro bioassays for (anti-)androgenic activities showed that TBBPA had a weak androgenic activity in vitro with recombinant yeast systems carrying human androgen receptor (hAR). In the in vivo bioassays, the gene expression patterns of vitellogenin (Vtg), estrogen receptors (ER alpha and ER beta), and androgen receptors (AR alpha and AR beta) in adult males and juveniles after exposure to TBBPA for 60 days were evaluated. Significant up-regulation of Vtg, ER alpha, and ER beta mRNAs was observed in the liver after exposure to 500 nM of TBBPA. In the testis, the lowest concentration of TBBPA (50 nM) markedly induced Vtg, ER beta, and AR beta mRNA expression, but the same concentration significantly inhibited AR alpha mRNA expression. In addition, in juveniles, 100 nM of TBBPA significantly up-regulated the expression of Vtg, ER beta, and AR alpha mRNAs. However, TBPPA did not cause histological alterations in the liver and testis of adult male mosquitofish. The results from this present study suggest that TBBPA could display low but multiple hormonal activities despite its low toxicity to mosquitofish. (C) 2013 Elsevier Inc. All rights reserved.