In our recent studies, Firemaster® 550 (FM550), a FR replacement for pentabromodiphenyl ethers (pentaBDEs), activated PPARγ and initiated adipocyte differentiation in vitro (Pillai et al. 2014), which may explain why perinatal exposure to FM550 in rats led to obesity and glucose sensitivity (Patisaul et al. 2013). Here, PPARG is linked to obesity due to melanocortin 4 receptor deficiency.