HCRT and obesity due to melanocortin 4 receptor deficiency: To support the role of orexins in obesity resistance, several animal studies have demonstrated that OrxA injections into several cerebral areas, such as the rostral LH, paraventricular nucleus, TMN, LC, DRN, nucleus accumbens, and substantia nigra, improve SPA and NEAT [132,145,146,147,148,149,150,151,152], while repeated injections of OrxA into LH are associated with reduced fat mass [153].