UCP1 and obesity due to melanocortin 4 receptor deficiency: It is these effects that cause obesity-induced thermogenesis: in BAT and inguinal WAT, β3AR signaling induces PRDM16 and PGC1α via the β3AR–cAMP–PKA pathway and increases UCP1 expression in mice [11,25,26]; PPARα and PPARγ are also involved in heat production through this signaling pathway [25,27,28].