The identification of β3-adrenergic receptor in brown adipocytes kindled new hope since this receptor is an important mediator of SNS-generated thermogenesis and fat oxidation.193 In rodents, ablation of BAT and all β-adrenergic receptors causes obesity, and transgenic mice overexpressing UCP1 are protected from diet-induced obesity. Here, UCP1 is linked to obesity due to melanocortin 4 receptor deficiency.