Sex ‐specific endocrine‐disrupting effects of three halogenated chemicals in Japanese medaka

The objective of this study was to assess sex differences on thyroid and estrogenic effects after exposure of Japanese medaka (Oryzias latipes, SK2MC) to halogenated compounds. This strain is an excellent model for these studies as sex can be determined non ‐destructively a few hours postfertilization. Medaka embryos were exposed to sublethal concentrations of Tris(1,3‐dichloro‐2‐propyl) phosphate (TDCPP, 0.019 mg/L), perfluorooctanoic acid (PFOA, 4.7 mg/L) and its next generation alternative, perfluorobutyric acid (PFBA, 137 mg/L). Methimaz ole (inhibits thyroid hormone synthesis) and the thyroid hormone triiodothyronine served as reference controls. Fish were exposed throughout embryo development until 10 days postfertilization. Females displayed significantly larger swim bladders (which are under thyroid hormone control) after expos ure to all chemicals with the exception of triiodothyronine, which caused the opposite effect. Females exposed to TDCPP and PFOA had increased expression of vitellogenin and exposure to PFOA upregulated expression of multiple thyroid‐related genes. Upregulation of estrogenic‐regulated genes afte r exposure to TDCPP, PFOA and methimazole was only observed in males. Overall, our results suggest that females and males show an estrogenic response when exposed to these halogenated chemicals and that females appear more susceptible to thyroid‐induced swim bladder dysfunction compared with males . These results further confirm the im...
Source: Journal of Applied Toxicology - Category: Toxicology Authors: Tags: RESEARCH ARTICLE Source Type: research