The reciprocal switching of two thyroid hormone-activating and -inactivating enzyme genes is involved in the photoperiodic gonadal response of Japanese quail.
The reciprocal switching of two thyroid hormone-activating and -inactivating enzyme genes is involved in the photoperiodic gonadal response of Japanese quail.
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DOI：
10.1210/en.2005-0057
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发表时间：
2005-06
期刊：
影响因子：
4.8
通讯作者：
S. Yasuo;Miwa Watanabe;N. Nakao;T. Takagi;B. Follett;S. Ebihara;T. Yoshimura
中科院分区：
文献类型：
--
作者：
S. Yasuo;Miwa Watanabe;N. Nakao;T. Takagi;B. Follett;S. Ebihara;T. Yoshimura
光周期时间测量的分子机制在任何生物中都没有很好的理解。然而，相对最近，甲状腺激素在光周期中起着重要作用变得越来越清楚，并且在以前的研究中，我们报道了日本鹌鹑的长日照增加了下丘脑的T（3）和甲状腺素活化酶（2型碘甲状腺原氨酸脱碘酶）的水平。本研究将这些观察结果扩展到测量甲状腺癌失活酶3型脱碘酶的基因水平。暴露于长日照后，水平下降，但短日照下增加。然后，在鹌鹑暴露于一个漫长的一天中发生的精确定时的光诱导过程中，分析了这两个基因的变化。这两个基因开关是光诱导过程中最早记录的事件，总体而言，这些相互变化提供了在大脑中触发光诱导的部位相当精确地调节活性脑甲状腺激素浓度的潜力。
The molecular mechanisms underlying photoperiodic time measurement are not well understood in any organism. Relatively recently, however, it has become clear that thyroid hormones play an important role in photoperiodism, and in a previous study we reported that long daylengths in Japanese quail increase hypothalamic levels of T(3) and of the thyroid hormone-activating enzyme, type 2 iodothyronine deiodinase. The present study extends these observations to measure gene levels of the thyroid hormone-inactivating enzyme, type 3 deiodinase. Levels decreased after exposure to long days, but increased under short days. Changes in the two genes were then analyzed during the precisely timed photoinduction that occurs in quail exposed to a single long day. The two gene switches are the earliest events yet recorded in the photoinduction process, and overall, these reciprocal changes offer the potential to regulate active brain thyroid hormone concentrations rather precisely at the site in the brain where photoinduction is triggered.