The house musk shrew, Suncus murinus as unique laboratory animal model for estimation of thyroid hormone function

麝香鼩（Suncus murinus）作为评估甲状腺激素功能的独特实验动物模型

基本信息

批准号：
14580797
负责人：
ODA Sen-ichi
金额：
$ 2.37万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

1) The house musk shrew Suncus murinus belongs to the most primitive mammalian oder Insectivora. This species is widely distributed in hot climate area from East Africa to East Asia2) We found that the type-1 iodothyronine deiodinase (D1) activity in shrew liver was one third of that in the rat liver. The other hand, D2 activity was higher level. To elucidate the mechanism for those activities, we cloned the D1 and D2 cDNA from the shrew liver. RT-PCR was performed using different sets of primers, which were designed based on conserved amino acid sequences of the D1, D2 and D3 among different species. The cloned cDNAs contain the entire open reading frame. A putative selenocystein (Sec) was identified, which is conserved among mammalian species. Cloned the D1 and D2 cDNA from the shrew were comparable same to other mammal species3) Blood T3 level in the shrew was stable at the fasting status, but T3 level in the mouse and rat was decreased. D1 mRNA in the liver and D2 mRNA in the brown adipose tissue were reduced but D2 activities in the brain were incresed. Brain D2 activities may support normal blood T3 level in the shrew4) Blood T3 level in the shrew was constant in fasting status and basic metabolism was not reduced in fasting status. So, the shrew is soon died in fasting status. The shrew is so unique animal to study the mechanism of thyroid hormone metabolism comparable to the rats and mice

1）家麝鼩Suncus murinus属于最原始的哺乳动物食虫目。该物种广泛分布于从东非到东亚的炎热气候地区2)我们发现鼩鼱肝脏中的1型碘甲状腺氨酸脱碘酶(D1)活性是大鼠肝脏中的三分之一。另一方面，D2 活性较高。为了阐明这些活性的机制，我们从鼩鼱肝脏中克隆了 D1 和 D2 cDNA。使用不同组的引物进行RT-PCR，这些引物是根据不同物种之间D1、D2和D3的保守氨基酸序列设计的。克隆的 cDNA 包含整个开放阅读框。鉴定出一种推定的硒代半胱氨酸（Sec），它在哺乳动物物种中是保守的。从鼩鼱克隆的D1和D2 cDNA与其他哺乳动物物种相当。3)鼩鼱的血液T3水平在禁食状态下稳定，但小鼠和大鼠的T3水平下降。肝脏中的 D1 mRNA 和棕色脂肪组织中的 D2 mRNA 减少，但大脑中的 D2 活性增加。脑 D2 活动可能支持鼩鼱正常的血液 T3 水平4) 鼩鼱的血液 T3 水平在禁食状态下保持恒定，并且在禁食状态下基础代谢没有降低。于是，鼩鼱很快就在禁食状态下死亡了。鼩鼱是如此独特的动物，研究甲状腺激素代谢机制可与大鼠和小鼠相媲美