Artificial light at night (ALAN) can affect the physiology and behavior of animals because it alters the natural rhythm of light and darkness. Thyroid hormones (TH) are partially regulated by the light information of photoperiod and are involved in metabolic adjustments to daily and seasonal changes in the environment, such as larval and juvenile development, somatic growth and reproduction. ALAN can change photoperiodic information and might thereby lead to changes in thyroid metabolism, but so far research on this topic is scarce. Therefore, we tested in two different experiments the effects of nocturnal illumination at a wide range of light intensities on TH in plasma of Eurasian perch (Perca fluviatilis). Total 3,3′,5-triiodo-L-thyronine (T3) was significantly affected by ALAN and reduced at the highest tested intensity of 100 lx after only two weeks of exposure. Although total L-thyroxine (T4) was not significantly affected, the ratio of T3 to T4 tended to slightly decrease at 100 lx. In a second low-light experiment ALAN did not have clear effects on T3, T4 or the ratio of T3 to T4 at intensities between 0.01 lx and 1 lx. The results show first signs of endocrine disruption in thyroid metabolism after a relatively short ALAN exposure of two weeks under high-intensity streetlight conditions. Misbalanced thyroidal status can have serious implications for metabolic rates as well as developmental and reproductive processes.

中文翻译：

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晚上在欧亚鲈鱼Perca fluviatilis中暴露于人造光两周后，甲状腺激素的失衡

夜间人造光（ALAN）会影响动物的生理和行为，因为它会改变光与暗的自然节奏。甲状腺激素（TH）受光周期的光信息部分调节，并参与环境中每日和季节性变化的代谢调整，例如幼虫和幼体发育，体细胞生长和繁殖。ALAN可以改变光周期信息，从而可能导致甲状腺代谢的改变，但是到目前为止，关于该主题的研究还很少。因此，我们在两个不同的实验中测试了夜间照明在不同光强度下对欧亚鲈（Perca fluviatilis）血浆中TH的影响）。暴露仅两周后，总3,3'，5-三碘-L-甲状腺素（T3）受到ALAN的显着影响，并在最高测试强度100 lx时降低。尽管总的L-甲状腺素（T4）并未受到显着影响，但在100 lx时，T3与T4的比例趋于稍微降低。在第二个弱光实验中，ALAN在0.01 lx和1 lx之间的强度下对T3，T4或T3与T4的比率没有明显影响。结果表明，在高强度路灯条件下，相对较短的ALAN暴露时间为两周后，甲状腺代谢的内分泌破坏的初步迹象。甲状腺状态失衡可能严重影响代谢率以及发育和生殖过程。