Skinny mice defy obesity 瘦老鼠挑战肥胖

Lean mouse: Hope for the clinically obese

精瘦的老鼠：肥胖症的希望

Genetically engineered mice which never put on weight could hold the key to a fat- free future for humans, say scientists.

Researchers at Smith Kline Beecham and Cambridge University, UK, have developed mice that eat far more than normal but remain leaner and lighter.

The lab rodents over-produce a human protein which ensures food is turned into heat, rather than stored as fat.

Reporting in the journal Nature, Dr John Clapham and colleagues say their mice make large amounts of Uncoupling Protein 3 (UCP-3) in the mitochondria of their muscle cells.

Mitochondria are often described as the tiny internal combustion engines of cells. They unlock the energy contained in food to make a chemical fuel called adenosine triphosphate (ATP).

But extra UCP-3 causes the mice to burn off energy without making ATP - their bodies produce more heat instead. This process makes the metabolic rate of the transgenic mice step up a gear. As a result, they are able to eat large amounts of food yet weigh less than normal mice.

科学家们说，从不增重的转基因老鼠是人类将来摆脱肥胖的钥匙。

Smith Kline Beecham和英国剑桥大学的研究人员培养出一些老鼠，它们超量进食却能保持身体轻瘦。

这些实验室里的啮齿动物超量产生一种人体蛋白质，这种蛋白质保证食物转化成热量而不是以脂肪形式储存。

在《自然》杂志上，约翰－克拉彭博士和他的同事们说，他们培养的这些老鼠在肌肉细胞的线粒体中产生大量解藕连蛋白质3（UCP-3）。

线粒体通常被形容成细胞的微型内燃机。它们将食物中的能量转化成一种叫做三磷酸缐苷(ATP)的化学燃料。

但多余的UCP-3使这些老鼠将能量耗光而不产生ATP－它们的身体产生的是更多的热量。这一过程使这些转基因老鼠新陈代谢加快。结果就是，它们吃大量食物，却比正常老鼠要轻。