title: Effects of a 5-day treatment with the UV-filter octyl-methoxycinnamate (OMC) on the function of the hypothalamo-pituitary-thyroid function in rats.
abstract: Octyl-methoxycinnamate (OMC) is one of the most frequently used UV-filters in sunscreens to protect the skin against the noxious influence of UV radiation. Recently, OMC was suspected to act as an "endocrine active chemical" (EAC) with estrogenic actions. While EACs have been investigated thoroughly for interference with reproductive function in mammalians, surprisingly little efforts have been made to investigate an interference of EACs with the hypothalamo-pituitary-thyroid (HPT) axis despite the expression of estrogen receptors in all parts of this axis. Therefore, we conducted an in vivo study with ovariectomised rats treated for 5 days with different doses of OMC or 17beta-estradiol (E2) as a control. Determined parameters comprised serum levels of TSH, T4 and T3, hypothalamic TRH mRNA expression, protein-expression of the sodium-iodide-symporter (NIS) and the TSH receptor and the activities of thyroid peroxidase (TPO) in the thyroid and the T3-responsive hepatic type I 5'deiodinase (Dio1) in the liver. While E2 did not affect TSH-, T4- or T3-levels, OMC caused a dose-dependent decrease of serum concentrations of all of these hormones. TRH expression remained unaffected, while in the thyroid, expression of the TSH receptor but not of NIS was stimulated by OMC. TPO activity was unaltered but Dio1 activity was reduced by OMC. Thus, our results demonstrate a non-estrogenic interference of OMC within the rodent HPT axis with inadequate feedback response to impaired thyroid hormone status, indicated by decreased serum thyroid hormone and hepatic Dio1 levels.
authors.affiliation: Department of Clinical and Experimental Endocrinology, University of Goettingen, Robert-Koch-Str. 40, 37075 Goettingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Klammer
authors.forename: Christiane
authors.initials: C
authors.lastname: Schlecht
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wuttke
authors.forename: Cornelia
authors.initials: C
authors.lastname: Schmutzler
authors.forename: Inka
authors.initials: I
authors.lastname: Gotthardt
authors.forename: Josef
authors.initials: J
authors.lastname: Köhrle
authors.forename: Hubertus
authors.initials: H
authors.lastname: Jarry
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002934:Cinnamates / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000502:physiology; D007453:Iodide Peroxidase / Q000378:metabolism; D007455:Iodine / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D010052:Ovariectomy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011989:Receptors, Thyrotropin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D027981:Symporters / Q000378:metabolism; D013954:Thyroglobulin / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism; D013997:Time Factors; D014284:Triiodothyronine / Q000378:metabolism; D000099209:Sodium-Iodide Symporters
chemical_list: D002934:Cinnamates; D007453:Iodide Peroxidase; D007455:Iodine; D012333:RNA, Messenger; D011989:Receptors, Thyrotropin; D013473:Sunscreening Agents; D027981:Symporters; D013954:Thyroglobulin; D013972:Thyrotropin; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine; D014284:Triiodothyronine; D000099209:Sodium-Iodide Symporters; C118580:octylmethoxycinnamate; C109812:iodothyronine deiodinase type I