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首页> 外文期刊>Reviews in Toxicology >Endocrine effects of episodic Polychlorinated Biphenyl (PCB) congeners
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Endocrine effects of episodic Polychlorinated Biphenyl (PCB) congeners

机译：间歇性多氯联苯（PCB）同类物的内分泌作用

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Polychlorinated biphenyl (PCB) congeners which do not persist in homeotherms are often unreported in epidemiology studies because they occur at low frequencies in single-time samples and are sometimes considered nontoxic. They occur at high proportions in exposure sources such as air, plants and fish so it is important to determine if episodes of brief exposure may cause adverse effects. Some PCB congeners readily metabolized by mammals were tested in prepubertal female rats in a protocol mimickingepisodes of brief exposures. PCBs 18 (2,5,2'-triCB), 77 (3,4,3',4'-tetraCB), 95 (2,3,6,2',5'-pentaCB), 101 (2,4,5,2',5'-pentaCB), 110 (2,3,6,3',4'-pentaCB), and 149 (2,3,6,2',4',5'-hexaCB) have been shown to disrupt the hypothalamo-pituitary-thyroid (HPT) axis and cause changes in estrogen-sensitive tissues after 1 or 2 doses in rats. Mice responded in manners similar to some congeners in rats following slightly longer subacute exposures, but they were less susceptible to serum thyroxine depletion. Acute responses to the persistent PCB congeners 118 (2,4,5,3',4'-pentaCB), 126 (3,4,5,3',4'-pentaCB), and 153 (2,4,5,2',4',5'-hexaCB) were also different from published responses following subacute and/or chronic exposures. The collective responses which differ with time, dose and congener suggest multiple complex mechanisms for the episodic congeners and/or their metabolites which could interact with steady state exposures. Most perturbations are transient and probably not of concern for healthy adults, but the unexpected net acute responses could readily interfere with development. Accurate risk assessment for PCBs requires consideration of unabridged profiles of congener exposures.
机译：流行病学研究中未报告多氯联苯同源物（PCB）在同温线中不存在，因为它们在单次样品中的发生频率较低，有时被认为是无毒的。它们在空气，植物和鱼类等暴露源中的比例很高，因此确定短暂暴露事件是否可能引起不利影响非常重要。在青春期前的雌性大鼠中，采用模仿短暂暴露的方案对一些容易被哺乳动物代谢的PCB同系物进行了测试。 PCB 18（2,5,2'-triCB），77（3,4,3'，4'-tetraCB），95（2,3,6,2'，5'-pentaCB），101（2,4 ，5,2'，5'-pentaCB），110（2,3,6,3'，4'-pentaCB）和149（2,3,6,2'，4'，5'-hexaCB）具有研究表明，在1或2剂剂量的大鼠中，该物质会破坏下丘脑-垂体-甲状腺（HPT）轴并引起雌激素敏感性组织的变化。亚急性暴露时间稍长一些后，小鼠的反应方式与大鼠某些同类动物相似，但它们对血清甲状腺素消耗的敏感性较低。对持久性PCB同系物118（2,4,5,3'，4'-pentaCB），126（3,4,5,3'，4'-pentaCB）和153（2,4,5， 2'，4'，5'-hexaCB）也不同于亚急性和/或慢性暴露后已发表的反应。随时间，剂量和同类物而异的集体反应表明，对于情景同类物和/或其代谢物，可能与稳态暴露相互作用的多种复杂机制。大多数摄动是短暂的，健康成年人可能不关心，但是意外的净急性反应很容易干扰发育。要对多氯联苯进行准确的风险评估，就必须考虑同类接触的完整概貌。

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