Hansen Jacob B, Kristiansen Karsten
Department of Medical Biochemistry and Genetics, the Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
Biochem J. 2006 Sep 1;398(2):153-68. doi: 10.1042/BJ20060402.
Adipose tissue is a major endocrine organ that exerts a profound influence on whole-body homoeostasis. Two types of adipose tissue exist in mammals: WAT (white adipose tissue) and BAT (brown adipose tissue). WAT stores energy and is the largest energy reserve in mammals, whereas BAT, expressing UCP1 (uncoupling protein 1), can dissipate energy through adaptive thermogenesis. In rodents, ample evidence supports BAT as an organ counteracting obesity, whereas less is known about the presence and significance of BAT in humans. Despite the different functions of white and brown adipocytes, knowledge of factors differentially influencing the formation of white and brown fat cells is sparse. Here we summarize recent progress in the molecular understanding of white versus brown adipocyte differentiation, including novel insights into transcriptional and signal transduction pathways. Since expression of UCP1 is the hallmark of BAT and a key factor determining energy expenditure, we also review conditions associated with enhanced energy expenditure and UCP1 expression in WAT that may provide information on processes involved in brown adipocyte differentiation.
脂肪组织是一个主要的内分泌器官，对全身的稳态有着深远影响。哺乳动物体内存在两种脂肪组织：白色脂肪组织（WAT）和棕色脂肪组织（BAT）。白色脂肪组织储存能量，是哺乳动物最大的能量储备，而表达解偶联蛋白1（UCP1）的棕色脂肪组织可通过适应性产热消耗能量。在啮齿动物中，有充分证据支持棕色脂肪组织是对抗肥胖的器官，而关于棕色脂肪组织在人类中的存在及意义了解较少。尽管白色和棕色脂肪细胞功能不同，但对差异影响白色和棕色脂肪细胞形成的因素的了解却很稀少。在此，我们总结了白色与棕色脂肪细胞分化分子理解方面的最新进展，包括对转录和信号转导途径的新见解。由于UCP1的表达是棕色脂肪组织的标志以及决定能量消耗的关键因素，我们还综述了与白色脂肪组织中能量消耗增加和UCP1表达相关的情况，这些情况可能提供有关棕色脂肪细胞分化过程的信息。
