Brown adipose tissue and beyond: lipolysis and glycerolipid cycling in thermogenesis.

Abstract

Following cold exposure, brown adipose tissue (BAT) generates heat through uncoupling protein 1-mediated thermogenesis. Intracellular lipolysis, mediated by neutral lipases, provides nonesterified fatty acids that fuel BAT mitochondrial respiration and uncoupling. In the present review, we provide current knowledge on the neuroendocrine control of intracellular lipolysis in brown adipocytes and discuss how the intracellular lipolytic machinery is important for the thermogenic activity of BAT. We also examine the importance of glycerolipid cycling and white adipose tissue (WAT) lipolysis in cold-induced thermogenesis. We discuss recent evidence suggesting a significant role for other organs, such as the liver and cardiovascular system, in nonshivering thermogenesis. Beyond BAT, interorgan glycerolipid cycling between WAT and lean organs may contribute significantly to whole-body thermogenic responses.