Brown and Beige Fat: Physiological Roles beyond Heat Generation

Since brown adipose tissue (BAT) dissipates energy through UCP1, BAT has garnered attention as a therapeutic intervention for obesity and metabolic diseases including type 2 diabetes. As we better understand the physiological roles of classical brown and beige adipocytes, it is becoming clear that BAT is not simply a heat-generating organ. Increased beige fat mass in response to a variety of external/internal cues is associated with significant improvements in glucose and lipid homeostasis that may not be entirely mediated by UCP1. We aim to discuss recent insights regarding the developmental lineages, molecular regulation, and new functions for brown and beige adipocytes. Kajimura and colleagues propose the new idea that BAT is not simply a heat-generating organ. In addition to recent findings regarding the developmental lineages and molecular regulation of brown and beige adipocytes, they discuss the adipocytes’ roles in glucose and lipid homeostasis that may go beyond heat production through UCP1.