光照抑制达乌尔黄鼠入眠启动的能源物质转变的生化机制

Biochemical mechanism of metabolic substrate conversion at the start of hibernation of Daurian ground squirrel inhibited by light

生理生态学研究中的一个重要内容是动物对环境的适应策略。光周期是自然界中重要的环境因子。冬眠哺乳动物感受到光周期的缩短从而感知冬天的来临,进而在生理上表现出适应性调节准备进入冬眠状态。前期的研究表明光照在一定程度上抑制典型的贮脂越冬的冬眠动物达乌尔黄鼠冬眠的启动。以达乌尔黄鼠为研究对象,对比光照(12L∶12D)和恒黑(0L∶24D)对其入眠影响的糖和脂肪代谢酶活性的变化。研究结果显示:1)两种条件下达乌尔黄鼠肝脏中糖酵解过程的3种限速酶,丙酮酸激酶(pyruvate kinase,PK)、己糖激酶(hexokinase,HK)、磷酸果糖激酶(phosphofructokinase,PFK)和脂肪酸分解代谢的限速酶、肉碱脂酰转移酶1(carnitine acyltransferase1,CACT1)的活性并无显著差异。2)无论有光照还是恒黑条件,出现冬眠状态的达乌尔黄鼠肝脏中CACT1的活性比活跃状态的黄鼠显著增高;心肌及白色脂肪组织(WAT)中丙酮酸脱氢酶(pyruvate dehydrogenase,PDH)的活性也出现显著差异。这是动物对入眠后机体代谢的主要能源由糖类转变为体脂的适应。

Seasonal change in photoperiod is an important environmental factor for mammals to adjust some physiological processes and it is an important content in physiological ecology. Hibernating mammals feel the shortening of photoperiod and realize the coming of winter, then they adjust themselves in physiological behavior and prepare into hibernation. Previous studies indicate that light to some extent inhibit the start of hibernation of Daurian ground squirrel. This article took Daurian ground squirrel as the object of study and conducted comparison of two different light conditions, light （12L ： 12D） and constant dark （0L t 24D）. We studied the effect on squirrels＇ hibernation of glucose and fat metabolism enzyme activity change. The results are as follows： 1） Under the two conditions, the activity of four key enzyme involved in glycolysis and the fatty acid fl oxidation process, pyruvate kinase,hexokinase,phosphofructokinase and carnitine acyl transferase 1 did not have significant difference. 2） No matter the treatment, the activity of CACTI in the liver of hibernating squirrels increased remarkably compared with the active ones. The activity of PDH in heart and WAT also appears significant difference. This is the adjustment to environment for animals＇ metabolic substrate conversion from carbohydrate to fat.