Sepkovic D W, Byrne J J
Food Chem Toxicol. 1984 Sep;22(9):743-7. doi: 10.1016/0278-6915(84)90203-5.
These studies were designed to elucidate the effects on thyroid function and thyroid-hormone activity of the long-term administration of low doses of four polyhalogenated aromatic compounds. The compounds studied were the polychlorinated biphenyls (PCBs) Aroclor 1254 and Aroclor 1242, and the polybrominated biphenyls (PBBs) hexabromobiphenyl and octabromobiphenyl. Groups of eight female Sprague-Dawley rats, specified pathogen free, were fed a diet containing 50 ppm of one of the polyhalogenated biphenyls or control diet for 7 months. Significant effects on serum triiodothyronine (T3) were observed in the group given Aroclor 1254. Analysis of kinetic data revealed a decrease in T3 degradation rate and an increase of biological half-life after long-term exposure to Aroclor 1254. The T3 distribution space was increased in both groups treated with PCB, suggesting that PCB intoxication may open additional fluid pools to T3, possibly because of cell damage. Analysis of values for the same parameters for rats treated with PBBs showed less marked effects. The results of this study indicate that PCBs exert a direct effect on the thyroid gland and that the rate of synthesis of T3 may be reduced, and suggest that the mechanism of thyroid-hormone synthesis may be impaired.
这些研究旨在阐明长期低剂量施用四种多卤代芳香化合物对甲状腺功能和甲状腺激素活性的影响。所研究的化合物为多氯联苯（PCBs）氯丹1254和氯丹1242，以及多溴联苯（PBBs）六溴联苯和八溴联苯。将八组特定病原体-free的雌性Sprague-Dawley大鼠，喂食含50 ppm多卤代联苯之一的饮食或对照饮食7个月。在给予氯丹1254的组中观察到对血清三碘甲状腺原氨酸（T3）有显著影响。动力学数据分析显示，长期接触氯丹1254后，T3降解率降低，生物半衰期延长。在两组接受PCB处理的大鼠中，T3分布空间均增加，这表明PCB中毒可能会为T3打开额外的体液池，可能是由于细胞损伤。对接受PBBs处理的大鼠相同参数值的分析显示影响不太明显。本研究结果表明，PCBs对甲状腺有直接作用，T3合成速率可能降低，并提示甲状腺激素合成机制可能受损。
