棕色脂肪可以幫助消耗卡路里

    　而脂肪也有兩種。分子組成的白色脂肪會儲存卡路里，已導致全球愈來愈常見的肥胖現象，其後果包括糖尿病心臟病等。

There are two types of fat or adipose tissue in the human body, brown fat, with the primary function of burning calories to generate body heat, and white fat, which acts as an energy store. Now the surprise finding that brown fat cells are a derivative of the skeletal muscle lineage may prompt a rethink on our view of the relationship between these two tissues. Previously most models of fat development have suggested that brown and white fat cells arise from a common adipogenic precursor cell, but in vivo lineage tracing shows that brown fat cells arise from myoblastic cells that express the Myf5 gene, a marker thus far found only in muscle cells. And PRDM16, a zinc-finger protein known to stimulate brown fat-selective gene expression, can powerfully regulate the bidirectional cell fate switch between muscle and brown fat. As a dominant regulator of the brown fat cell fate, PRDM16 may have potential use therapeutically in obesity, as may compounds able to induce PRDM16 expression in white fat or muscle progenitors. The cover represents brown fat cells in which PRDM16 expression is suppressed by shRNA, with myocytes shown in red and fat cells and other cell types marked by blue nuclei.

http://www.nature.com/nature/journal/v454/n7207/covers/index.html

Nature Cover art: Eric Smith.