Brown adipose tissue

Brown adipose tissue (BAT) or brown fat is one of two types of adipose tissue found in mammals. It is named for its brown color, which is due to the high density of mitochondria and rich vascularization. Unlike white adipose tissue (WAT), which stores energy in the form of triglycerides, BAT is specialized for energy expenditure. It is primarily located in the neck and large blood vessels of the thorax, where it generates heat by burning fatty acids and glucose.

Function

The primary function of BAT is thermogenesis (heat production) in response to cold exposure or diet. This is achieved through the action of the protein uncoupling protein 1 (UCP1), which is uniquely expressed in the mitochondria of brown adipocytes. UCP1 uncouples oxidative phosphorylation from ATP production, allowing energy to be dissipated as heat.

Development

Brown adipocytes are derived from a common myogenic factor 5 (Myf5)-positive progenitor with skeletal muscle. The development of BAT is regulated by a complex network of transcription factors, including PR domain containing 16 (PRDM16), peroxisome proliferator-activated receptor gamma (PPARγ), and CCAAT/enhancer-binding protein (C/EBP) family members.

Clinical significance

BAT has been the focus of research for its potential role in combating obesity and metabolic syndrome. Activation of BAT increases energy expenditure and can reduce body weight. Furthermore, BAT activity is inversely correlated with body mass index (BMI) and age, suggesting a potential therapeutic role for BAT in obesity and type 2 diabetes.

See also

• Adipose tissue
• White adipose tissue
• Thermogenesis
• Uncoupling protein
• Obesity
• Metabolic syndrome