在线英语听力室_免费在线英语听力学习网站

Leptin is a hormone¹ made by fat cells that tells you when you're full. If you didn't have leptin---and some people don't---you’d eat way too much, get real fat and almost certainly develop diabetes².  Leptin acts like a natural appetite suppressant.  Kids born without the hormone can top a hundred pounds before they hit kindergarten.  And mice without leptin are sluggish³ balls of blubber.  But how does leptin work as dietary wonders?  To find out, scientists took mice that don't respond to leptin because they lack the receptor to which it binds⁴.  They then added the leptin receptor to one small group of brain cells.  The result, the enhanced mice eat less and spend twice as much time running around.  Even better, being able to sense leptin returns their blood sugar to normal levels, staving off diabetes.  The study appears in the June 2nd issue of the journal Cell Metabolism⁵.  Could be that these brain cells in response to leptin convince muscles to remove more sugar from the blood or they might be telling the liver to stop dumping sugar into the bloodstream in the first place. Either way you get healthier mice and maybe someday healthier people too.  Thanks to researchers who saw a difficult problem and leapt in.

Thanks for the minute for Scientific American's 60-second Science.  I'm Karen Hopkin.