Figure 3.

Schematic overview of function of sympathetic innervation of white and brown adipose tissues in the regulation of lipid metabolism. Schematic diagram indicating lipolysis and thermogenesis in white and brown adipocytes respectively regulated by sympathetic innervation. In white adipocytes, sympathetic innervation regulates a cascade of lipolysis to convert stored triglycerides (TG) to free fatty acids (FFA) and glycerol that can be used as fuels of other tissues. In brown adipocytes, sympathetic innervation regulates non-shivering thermogenesis. FFAs are transferred into mitochondria, primarily by carnitine palmitoyltransferase 1 (CPT1), and serve as fuel for β-oxidation. UCP1 is activated to disassociate respiratory chain from ATP production, and ultimately dissipates energy as heat.