Expression of a chimeric retroviral-lipase mRNA confers enhanced lipolysis in a hibernating mammal
Expression of a chimeric retroviral-lipase mRNA confers enhanced lipolysis in a hibernating mammal
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DOI：
10.1152/ajpregu.2001.281.4.r1186
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发表时间：
2001-10-01
影响因子：
2.8
通讯作者：
Andrews, MT
中科院分区：
文献类型：
--
作者：
Bauer, VW;Squire, TL;Andrews, MT
冬眠的哺乳动物可以在不进食的情况下存活几个月，这是通过限制它们的碳水化合物催化剂和使用储存在白色脂肪组织（WAT）中的三酰甘油作为它们的主要燃料来源。在这里，我们表明，通常在肠道中发现的脂解酶，胰腺三酰甘油脂肪酶（PTL），是在冬眠的13线地松鼠（黄鼠tridecemlineatus）的WAT表达。在WAT中表达的PTL是由一种不寻常的嵌合逆转录病毒-PTL mRNA编码的，其类似于比在其他地松鼠组织中发现的主要PTL信息长500个碱基。季节性测量检测嵌合mRNA和PTL酶活性在WAT冬眠前和冬眠期间，都显示出它们的最低观察水平冬眠后1周在3月中旬结束。除了激素敏感性脂肪酶（通常负责WAT中三酰甘油水解的酶）之外，还表达PTL。由于这两种酶的独特的催化和调节特性，这种双三酰甘油脂肪酶系统提供了一种手段，通过这种手段，冬眠的13线地松鼠的燃料需求可以得到满足，而不中断。
Hibernating mammals can survive several months without feeding by limiting their carbohydrate catabolism and using triacylglycerols stored in white adipose tissue (WAT) as their primary source of fuel. Here we show that a lipolytic enzyme normally found in the gut, pancreatic triacylglycerol lipase (PTL), is expressed in WAT of hibernating 13-lined ground squirrels (Spermophilus tridecemlineatus). PTL expressed in WAT is encoded by an unusual chimeric retroviral-PTL mRNA similar to 500 bases longer than the predominant PTL message found in other ground squirrel tissues. Seasonal measurements detect the chimeric mRNA and PTL enzymatic activity in WAT before and during hibernation, with both showing their lowest observed levels 1 wk after hibernation concludes in mid-March. PTL is expressed in addition to hormone-sensitive lipase, the enzyme typically responsible for hydrolysis of triacylglycerols in WAT. Because of the distinct catalytic and regulatory properties of both enzymes, this dual-triacylglycerol lipase system provides a means by which the fuel requirements of hibernating 13-lined ground squirrels can be met without interruption.