title: T-screen and yeast assay for the detection of the thyroid-disrupting activities of cadmium, mercury, and zinc.
abstract: In the present study, a two-hybrid yeast bioassay and a T-screen were used to screen for the thyroid receptor (TR)-disrupting activity of select metallic compounds (CdCl2, ZnCl2, HgCl2, CuSO4, MnSO4, and MgSO4). The results reveal that none of the tested metallic compounds showed TR-agonistic activity, whereas ZnCl2, HgCl2, and CdCl2 demonstrated TR antagonism. For the yeast assay, the dose-response relationship of these metallic compounds was established, and the concentrations producing 20 % of the maximum effect of ZnCl2, HgCl2, and CdCl2 were 9.1 × 10(-5), 3.2 × 10(-6), and 1.2 × 10(-6) mol/L, respectively. The T-screen also supported the finding that ZnCl2, HgCl2, and CdCl2 decreased the cell proliferation at concentrations ranging from 10(-6) to 10(-4) mol/L. Furthermore, the thyroid-disrupting activity of metallic compounds in environmental water samples collected from the Guanting Reservoir, Beijing, China was evaluated. Solid-phase extraction was used to separate the organic extracts, and a modified two-hybrid yeast bioassay revealed that the metallic compounds in the water samples could affect thyroid hormone-induced signaling by decreasing the binding of the thyroid hormone. The addition of ethylenediaminetetraacetic acid (30 mg/L) could eliminate the effects. Thus, the cause(s) of the thyroid toxicity in the water samples appeared to be partly related to the metallic compounds.
authors: Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China. lijian@bnu.edu.cn.
authors: Jian
authors: J
authors: Li
authors: South China Institute of Environmental Science, Ministry of Environmental Protection, No. 7 West Street, Yuancun, Guangzhou, 510655, China.
authors: Yun
authors: Y
authors: Liu
authors: Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
authors: Dongdong
authors: D
authors: Kong
authors: Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
authors: Shujuan
authors: S
authors: Ren
authors: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing, 100085, China.
authors: Na
authors: N
authors: Li
mesh_terms: D000818:Animals; D000068476:Beijing; D001681:Biological Assay / Q000379:methods; D002104:Cadmium / Q000633:toxicity; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004492:Edetic Acid / Q000737:chemistry; D052244:Endocrine Disruptors / Q000633:toxicity*; D006801:Humans; D008628:Mercury / Q000633:toxicity; D019216:Metals, Heavy / Q000633:toxicity*; D051381:Rats; D011988:Receptors, Thyroid Hormone / Q000819:agonists / Q000037:antagonists & inhibitors; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015003:Yeasts / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015032:Zinc / Q000633:toxicity
chemical_list: D052244:Endocrine Disruptors; D019216:Metals, Heavy; D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones; D014874:Water Pollutants, Chemical; D002104:Cadmium; D004492:Edetic Acid; D008628:Mercury; D015032:Zinc
keywords: In vitro bioassay; Thyroid receptor; Thyroid-disrupting activity; Toxic metals