Thyroid and sex hormone disrupting effects of DEHTP at different life stages of zebrafish (Danio rerio)

Chemosphere. 2024 Apr 22:142105. doi: 10.1016/j.chemosphere.2024.142105. Online ahead of print.ABSTRACTDi(2-ethylhexyl) terephthalate (DEHTP) is an alternative plasticizer widely used in numerous consumer products, replacing di(2-ethylhexyl) phthalate (DEHP). Hence, DEHTP has been frequently detected in the environment and humans. As a structural isomer and functional analog of DEHP, DEHTP is a suspected endocrine disruptor. Here, we evaluated DEHTP thyroid-disrupting effects in embryo-larval and adult male zebrafish. We also investigated sex hormone disruption in the adult zebrafish. After 5- and 7-day exposure to DEHTP, significant increases in whole-body thyroid hormonal levels were observed in the larval fish. Down-regulation of several thyroid-regulating genes, including trh, tshβ, nis, and dio2, was observed, but only after 5-day exposure. Following a 21-day exposure, the adult male zebrafish exhibited a significant decrease in total triiodothyronine and an increase in thyroid-stimulating hormones. Potential changes in the deiodination of thyroid hormones, supported by the up-regulation of two deiodinases, dio1 and dio3a, along with the down-regulation of dio2, could explain hormonal changes in the adult zebrafish. Moreover, significant trends of decrease in estradiol and 11-ketotestosterone, along with increase of testosterone (T), were observed in the adult zebrafish. Up-regulation of several steroidogenic genes may explain elevated T, while up-regulated shbg may par...
Source: Chemosphere - Category: Chemistry Authors: Source Type: research