title: Thyroid endocrine disruption of acetochlor on zebrafish (Danio rerio) larvae.
abstract: The herbicide acetochlor is widely used and detected in the environment and biota, and has been suspected to disrupt the thyroid endocrine system, but underlying mechanisms have not yet been clarified. In the present study, zebrafish larvae (7 days post-fertilization) were exposed to a series concentration of acetochlor (0, 1, 3, 10, 30, 100 and 300 µg l(-1) ) within a 14-day window until 21 days post-fertilization. Thyroid hormones and mRNA expression profiles of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were analyzed. Exposure to the positive control, 3,5,3'-triiodothyronine (T3 ), altered the mRNA expression, suggesting that the HPT axis in the critical window of zebrafish responded to chemical exposure and could be used to evaluate the effects of chemicals on the thyroid endocrine system. The mRNA expressions of genes involved in thyroid hormone synthesis (tshβ, slc5a5 and tpo) were upregulated significantly with acetochlor treatment, which might be responsible for the increased thyroxine concentrations. The downregulation of genes related to thyroid hormone metabolism (dio1 and ugt1ab) and transport (ttr) in zebrafish larvae exposed to acetochlor might further explain the increased thyroxine levels and decreased T3 levels. The mRNA expression of the thyroid hormone receptor (trα) was also upregulated upon acetochlor exposure. Results suggested that acetochlor altered mRNA expression of the HPT axis-related genes and changed the whole body thyroid hormone levels in zebrafish larvae. It demonstrated that acetochlor could cause endocrine disruption of the thyroid system by simulating the biological activity of T3 . Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Jingjin
authors.initials: J
authors.lastname: Hu
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Shuying
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Youning
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Gui
authors.affiliation: Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
authors.forename: Guonian
authors.initials: G
authors.lastname: Zhu
mesh_terms: D000818:Animals; D052244:Endocrine Disruptors / Q000633:toxicity*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D014453:Glucuronosyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006540:Herbicides / Q000633:toxicity*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D007453:Iodide Peroxidase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D007928:Lethal Dose 50; D009994:Osmolar Concentration; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D027981:Symporters / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D013961:Thyroid Gland / Q000187:drug effects*; D037322:Thyrotropin, beta Subunit / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D014052:Toluidines / Q000633:toxicity*; D015027:Zebrafish / Q000254:growth & development / Q000378:metabolism; D029961:Zebrafish Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000099209:Sodium-Iodide Symporters
chemical_list: D052244:Endocrine Disruptors; D014453:Glucuronosyltransferase; D006540:Herbicides; D007453:Iodide Peroxidase; D012333:RNA, Messenger; D027981:Symporters; D037322:Thyrotropin, beta Subunit; D014052:Toluidines; D029961:Zebrafish Proteins; D000099209:Sodium-Iodide Symporters; C043377:acetochlor; C109812:iodothyronine deiodinase type I
keywords: acetochlor; endocrine disruption; thyroid; window phase; zebrafish