title: Effects of triclocarban, triclosan, and methyl triclosan on thyroid hormone action and stress in frog and mammalian culture systems.
abstract: Triclosan (TCS) and triclocarban (TCC) are widely used broad spectrum bactericides that are common pollutants of waterways and soils. Methyl triclosan (mTCS) is the predominant bacterial TCS metabolite. Previous studies have shown that TCS disrupts thyroid hormone (TH) action; however, the effects of mTCS or TCC are not known. The present study uses the cultured frog tadpole tail fin biopsy (C-fin) assay and the TH-responsive rat pituitary GH3 cell line to assess the effects of these three chemicals (1-1000 nM) on TH signaling and cellular stress within 48 h. mRNA abundance of TH receptor β, Rana larval keratin type I (TH-response), heat shock protein 30, and catalase (stress-response) was measured using quantitative real-time polymerase chain reaction in the C-fin assay. The TH-responsive gene transcripts encoding growth hormone, deiodinase I, and prolactin were measured in GH3 cells with the heat shock protein 70 transcript acting as a cellular stress indicator. We found alteration of stress indicators at a wide range of concentrations of TCS, mTCS, and TCC in both test systems. mTCS and TCC affected TH-responsive gene transcripts at the highest concentration in mammalian cells, whereas a modest effect included lower concentrations in the C-fin assay. In contrast, TCS did not affect TH-responsive transcripts. These results identify nontarget biological effects of these bacteriocides on amphibian and mammalian cells and suggest the TH-disrupting effects observed for TCS could be mediated through its metabolite.
authors.affiliation: Department of Biochemistry & Microbiology, University of Victoria, Victoria, B.C., Canada.
authors.forename: Ashley
authors.initials: A
authors.lastname: Hinther
authors.forename: Caleb M
authors.initials: CM
authors.lastname: Bromba
authors.forename: Jeremy E
authors.initials: JE
authors.lastname: Wulff
authors.forename: Caren C
authors.initials: CC
authors.lastname: Helbing
mesh_terms: D000818:Animals; D002224:Carbanilides / Q000633:toxicity*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism; D050890:HSP30 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007453:Iodide Peroxidase / Q000235:genetics / Q000378:metabolism; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000235:genetics; D008322:Mammals / Q000502:physiology*; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011898:Ranidae / Q000235:genetics / Q000502:physiology*; D051381:Rats; D013312:Stress, Physiological / Q000187:drug effects*; D037042:Thyroid Hormone Receptors beta / Q000187:drug effects / Q000378:metabolism; D013963:Thyroid Hormones / Q000494:pharmacology*; D014260:Triclosan / Q000031:analogs & derivatives* / Q000633:toxicity
chemical_list: D002224:Carbanilides; D050890:HSP30 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D037042:Thyroid Hormone Receptors beta; D013963:Thyroid Hormones; D014260:Triclosan; C502486:methyl triclosan; D007633:Keratins; D011388:Prolactin; D013006:Growth Hormone; C009540:triclocarban; D002374:Catalase; D007453:Iodide Peroxidase