Individual And Joint Toxic Effects Of Endocrine Disrupting Chemicals With Different Mode Of Actions On Medaka (Oryzias Latipes)

The study of endocrine disruption is being increasingly conducted at the mRNA level of genes, as this approach can yield insight into the modes of action. In this study, the physiological indictors and the transcriptional responses of a set of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis of Japanese medaka larve were examined after treatment with anti-breast cancer drug trilostane (TRI) and the pesticide fipronil(FIP) for 28 days. The results showed that TRI and FIP produced distinct expression profiles in a gender-specific manner. Especially, FIP significantly up-regulated the expression of vitellogenin (VTG).Then, the transcriptional responses of a set of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis and detoxification of Japanese adult medaka were examined after treatment with TRI and FIP for 72 hours. The results showed that TRI influenced greatly the expression of HPG axis-related genes. FIP caused a significant upregulation of detoxification genes and produced a great impact on the HPG axis for adult female,but not for the males.For a variety of pollutants presenting in environment at the same time, the study on comb lined effects of endocrine disrupting chemicals are needed for ecotoxicology. In this study, the transcriptional responses of a set of genes involved in the HPG axis of adult male Japanese medaka were examined after treatment with two model anti-androgens, vinclozolin (VIN) and flutamide (FLU)for 72 hours. The results showed that VIN and FLU produced great impacts on the HPG axis. Significantly up-regulations for the expression of AR in many tissues were observed after exposure to both chemicals. Thereafter, the fish were exposed to binary mixture containing TB and VIN/FLU for 72 hours. The exposure to the environmental androgen TB caused the suppression of the expression of many biomarkers, such as VTG. The coexposure to androgen and anti-androgen led to a complex effect of gene expression profiling.In conclusion, the data of present study demonstrate the effects of EDCs on medaka, both individually and in combination. This exploration will improve our current understanding of the actions of EDCs with different properties and will thereby contribute to the development of more effective methods for assessing environmental risk.