Figure 1.

The effects of cold on the induction of thermogenic active adipocyte. The secretion of norepinephrine (NE) directly from nervous sympathetic system or indirectly through catecholamine secretion by macrophage type 2 can stimulate glucose uptake in fat cells and improve the regulation of carbohydrate. Both glucose and triglycerides are used by UCP1 protein to increase thermogenesis. FFA: free fatty acid; M2: macrophages 2, SNS: sympathetic nervous system; PKA: protein kinase A; UCP1: uncoupling protein 1; PGC-1α: peroxisome proliferator-activated receptor-gamma coactivator alpha 1.