Himms-Hagen J
Department of Biochemistry, University of Ottawa, Ontario, Canada.
FASEB J. 1990 Aug;4(11):2890-8.
Energy expenditure for thermogenesis in brown adipose tissue (BAT) serves either to maintain body temperature in the cold or to waste food energy. It has roles in thermal balance and energy balance, and when defective, is usually associated with obesity. BAT can grow or atrophy; it is usually atrophied in obese animals. Control of BAT thermogenesis and growth is by the sympathetic nervous system, with integration of signals in the hypothalamus. Sensory nerves may also be involved. Understanding the control of growth and differentiation of BAT is important for discovering how to reactivate it is obesity. Studies on control of gene expression in BAT are concentrating on thermogenically important components such as the uncoupling protein (which allows BAT mitochondria to operate in a thermogenic uncoupled mode), lipoprotein lipase (which allows BAT to compete with white adipose tissue for dietary lipid), and thyroxine 5'-deiodinase (which allows endogenous triiodothyronine generation, part of the control of differentiation and growth of BAT). Differentiation of BAT cell precursors in culture has recently been achieved. BAT is present in adult humans and some anti-obesity drugs are targeted to stimulation of BAT thermogenesis. However, extrapolation to humans of results of studies of BAT requires the development of novel approaches to the noninvasive assessment of amount and function of human BAT.
棕色脂肪组织（BAT）产热的能量消耗要么用于在寒冷环境中维持体温，要么用于消耗食物能量。它在热平衡和能量平衡中发挥作用，功能出现缺陷时通常与肥胖有关。BAT可以生长或萎缩；在肥胖动物中它通常会萎缩。BAT产热和生长的控制由交感神经系统负责，信号在下丘脑整合。感觉神经可能也参与其中。了解BAT生长和分化的控制对于发现如何在肥胖状态下重新激活它很重要。对BAT中基因表达控制的研究集中在产热的重要成分上，如解偶联蛋白（它使BAT线粒体以产热解偶联模式运作）、脂蛋白脂肪酶（它使BAT能够与白色脂肪组织竞争膳食脂质）和甲状腺素5'-脱碘酶（它使内源性三碘甲状腺原氨酸生成，这是BAT分化和生长控制的一部分）。最近已实现了培养中BAT细胞前体的分化。BAT存在于成年人体内，一些抗肥胖药物的靶点是刺激BAT产热。然而，将BAT研究结果外推至人类需要开发新方法来无创评估人类BAT的数量和功能。
