EPAS1 and obesity due to melanocortin 4 receptor deficiency: Although previous reports have shown that hypoxia in obesity induces HIFs (2, 6, 12) and have illustrated the importance of proangiogenic responses in WAT and BAT adaptation to obesity (3, 8, 9, 11, 57), the involvement of HIF1α or HIF2α in this process was not clarified.