Thyrotrophin in the pars tuberalis triggers photoperiodic response
Thyrotrophin in the pars tuberalis triggers photoperiodic response
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DOI：
10.1038/nature06738
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发表时间：
2008-03-20
期刊：
影响因子：
64.8
通讯作者：
Yoshimura, Takashi
中科院分区：
文献类型：
--
作者：
Nakao, Nobuhiro;Ono, Hiroko;Yoshimura, Takashi
调节动物季节性繁殖以响应光周期变化的分子机制还不清楚。日本鹌鹑（Coturnix japonica）下丘脑内侧基底核（MBH）甲状腺激素激活酶（2型脱碘酶，DIO 2）基因的快速诱导表达是光周期信号转导途径中最早记录的事件。在这里，我们展示了鹌鹑MBH中与促黄体激素光诱导分泌启动相关的基因表达级联。我们发现了两种基因表达波。第一个在第一个漫长的一天黎明后约14小时开始，包括结节部促甲状腺素（TSH）β亚基表达增加;第二个发生在约4小时后，包括DIO 2表达增加。脑室内（ICV）注射TSH刺激短日龄鹌鹑性腺生长和DIO 2的表达，这表明是通过TSH受体-环腺苷酸（cAMP）信号通路介导的。因此，结节部TSH的增加似乎触发了长日照光诱导的季节性繁殖.
Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid- hormone- activating enzyme ( type 2 deiodinase, DIO2) in the mediobasal hypothalamus ( MBH) of the Japanese quail ( Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin ( TSH) beta- subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular ( ICV) administration of TSH to short- day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor - cyclic AMP ( cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long- day photoinduced seasonal breeding.