title: Possible effects of persistent organochlorinated pollutants cocktail on thyroid hormone levels and pituitary-thyroid interrelations.
abstract: In polluted district of Michalovce in East Slovakia (POLL) and two districts with background pollution (BCGR) 2046 adults (834 males and 1212 females aged 20-75 years) were examined. Serum levels of thyrotropin (TSH), free thyroxine (FT4), total triiodothyronine (TT3) and antithyroperoxidase antibodies (TPOab) were estimated by electrochemiluminiscent assay and also these of 15 polychlorinated biphenyl congeners (PCBs), p,p'-DDE, p,p'-DDT, hexachlorobenzene (HCB) and hexachlorocyclohexane were measured by high resolution gas chromatography/mass spectrometry. In addition, also dioxins, furans, coplanar- and mono-ortho-PCBs as well as selected hydroxylated and methylsulphonated PCBs and DDE metabolites were measured by appropriate methods based on gas chromatography/mass spectrometry principle. In POLL significantly higher levels of all organochlorines were found than these in BCGR. When pooled values from both areas were stratified in terms of PCBs level and treated as continuous variables, positive association of PCBs with FT4 and TT3 was found, the latter two being also mutually associated. However, within the category of PCBs level <530 ng/glipid (n=232) the association between PCBs and both the FT4 (p<0.09) and TT3 (p<0.03) was negative and any association of these was not found within the category of PCBs level of 531-1000 ng/g (n=691). In contrast, in the category of 531-2000 ng/g (n=1307) positive association appeared between PCBs and FT4 (p<0.001) as well as TT3 (p<0.05). Highly significant association of PCBs with FT4 (p<0.001) was further found in the categories with PCBs level of 1001-101414 ng/g (n=1307) and 2001-101414 (n=1123), while significant association with TT3 was observed only in the category of 531-2000 ng/g. Such findings suggest possible threshold level in positive effect of PCBs on FT4 and TT3 level which seems to be individual and located somewhere around the PCBs level of 1000 ng/g. However, highly significant negative association of both FT4 and TT3 with TSH was found in each of above indicated PCBs categories. Considerable difference in FT4 and TT3 level between large groups of subjects with the same range of PCBs level was also found suggesting different individual susceptibility to the effects of organochlorines. Among a total of 26 cases from POLL with very low TSH level (<0.5 mU l(-1)) 13 cases showed very high level of PCBs, FT4 and TT3, thus supporting a hypothesis on a novel sporadic form of high PCBs related peripheral subclinical hyperthyroidism possibly resulting from the long-term disruption of equilibrium between bound and free thyroxine in plasma by high PCBs level followed by a striking inhibition of TSH release from the pituitary.
authors: Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlárska 3, Bratislava, Slovakia. pavel.langer@savba.sk
authors: Pavel
authors: P
authors: Langer
authors: Anton
authors: A
authors: Kocan
authors: Mária
authors: M
authors: Tajtáková
authors: Zofia
authors: Z
authors: Rádiková
authors: Ján
authors: J
authors: Petrík
authors: Juraj
authors: J
authors: Koska
authors: Lucia
authors: L
authors: Ksinantová
authors: Richard
authors: R
authors: Imrich
authors: Miloslava
authors: M
authors: Hucková
authors: Jana
authors: J
authors: Chovancová
authors: Beáta
authors: B
authors: Drobná
authors: Stanislav
authors: S
authors: Jursa
authors: Aake
authors: A
authors: Bergman
authors: Maria
authors: M
authors: Athanasiadou
authors: Lotta
authors: L
authors: Hovander
authors: Daniela
authors: D
authors: Gasperíková
authors: Tomás
authors: T
authors: Trnovec
authors: Elena
authors: E
authors: Seböková
authors: Iwar
authors: I
authors: Klimes
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis; D052244:Endocrine Disruptors / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D006980:Hyperthyroidism / Q000139:chemically induced / Q000378:metabolism; D007453:Iodide Peroxidase / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000187:drug effects*; D011078:Polychlorinated Biphenyls / Q000633:toxicity; D018154:Slovakia; D013961:Thyroid Gland / Q000187:drug effects*; D013963:Thyroid Hormones / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood
chemical_list: D001323:Autoantibodies; D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D013963:Thyroid Hormones; D013972:Thyrotropin; D011078:Polychlorinated Biphenyls; D007453:Iodide Peroxidase