光周期和温度对中缅树产热能力的影响

EFFECTS OF PHOTOPERIOD AND TRMPERATURE ON THERMOGENESIS IN THE TREE SHREW (TUPAIA BELANGERI)

低温短光照诱导中缅树体重增加、体温降低、产热能力增强，静止代谢率增加的速度和比例高于非颤抖性产热；低温短光照刺激肝脏线粒体蛋白质量、线粒体氧化能力和细胞色素C氧化酶活性显著增加；短光照也刺激褐色脂肪组织总蛋白和线粒体蛋白基、线粒体状态IV呼吸：细胞色素C氧化酶、α-磷酸甘油氧化酶及T45’-脱碘酶活性显著提高。低温和短光照促使血清T3浓度增加、T4浓度不变。结果表明，中缅树的适应性产热特征不仅受到低温的显著影响，而且光周期也参与了适应性产热的调节．

The famlly, Tupaiidae, is a typical group of the Oriental in Asia, and it incltldes 16 living species. The central range of the family inhabited mainly in tropical zone of Southeast Asia. Among them the tree shrew, Tupaia belangeri, was the most northern species. With the increasing of altitude and latitude, the characteristics of therrnogenesis in small mammals show some changes. We were interested in the changes in individual thermogenesis, the oxidative activities of mitochondria and some hormones (T3, T4in serum) induced by temperature and photoperiod under acclimation. The resu1ts were shown as follows:1. When the animals were exposed to low temperature (51±1℃) for 28 days, the body mass, RMR and NST in short photoperiod (6L: 18D) were significantly higher than in long photoperiod (18L: 6D). Exposed to high temperature (30±1℃ ) for 28 days, the parameters in short photoperiod were higher than in long photoperiod.2. The short photoperiod under cold exposure induced significantly the increases of protein content, state Ⅳ and state Ⅲ respiration, and the activity of cytochrome C oxidase of liver mitochondrial. However, the same short photoperiod under heat exposure did not obviously induce these changes.3. The content of mitochondrial protein and the activity of cytochrome C oxidase in brow adipose tissue (BAT) were increased in short photoperiod and cold exposure; but the latter did not change significantly in different photoperiod and heat exposure. 4. After exposure to cold or to short photoperiod for 28 days, the activity of T45'-DII in BAT was obviously higher than to heat or long photoperiod. When exposed to cold and short photoperiod for 28 days, the concentration of T3 in serum increased, but the concentration of T4 was not different. Our results suggested that cold temperature and photoperiod have a significant effect on the thermoregulation of tree shrew. Low temperature was more important in thermoregulation than short photoperiod. The short photoperiod affected the adaptive thermogenesis by increasing the activity of T45'-DII in BAT. In addition, the liver of the tree shrew regulated thermogenesis in different photoperiod.