Brown adipose tissue (BAT) is a kind of facultative-thermogenic organ, especially importantin small mammals.The key element in BAT heat production is the uncoupling protein (UCP), a unique protein located in the inner membrane of BAT mitochondria. Thermogenic stimulation of this tissue opens the UCP's proton channel, results in a proton short-circuit.thus bypasses the relatively small amount of ATP synthetase present in BAT mitochondria resulting in a severalfold accelerated oxidative metabolism. The structral and functional state of BAT is regulated by many factors, such as norepinephrine, thyroid hormone, insulin. pH, and food, enviormental temperature etc.