FAS and obesity due to melanocortin 4 receptor deficiency: After activating AMPK, Rhizoma coptidis exerts its function as follows: (A) activation of AS160 and GLUT4 to promote glucose transportation; (B) regulation of PFK-2 to promote glycolysis; regulation of FAS and ACC to inhibit gluconeogenesis and glycogen formation; (C) inhibition of SREBP1c and its downstream PPARγ, FAS, and ACC1 to anti-obesity.