We previously reported that GHS-R ablation increased BAT thermogenesis by activating central sympathetic nervous system (SNS) mediated norepinephrine-induced β3-AR in BAT of aged mice, suggesting that different metabolic/physiological conditions such as aging and obesity may affect thermogenesis via both central and peripheral mechanisms [14]. This evidence concerns the gene GHSR and obesity due to melanocortin 4 receptor deficiency.