BAT function largely depends on angiogenesis (3, 57); by staining with fluorochrome-labeled isolectin B4, we found reduced vascularity in the BAT of obese AdHIF2KO mice (Fig. 8G) compared to that in littermate control mice, suggesting that HIF2α supports angiogenic processes in BAT in obesity. Here, EPAS1 is linked to obesity due to melanocortin 4 receptor deficiency.