As FABP-4 plays an important role in modulating lipid release and metabolism in adipocytes via its interaction with hormone-sensitive lipase (179) or PPARγ transcription factors (180), peroxynitrite-mediated nitration of FABP-4 may contribute to the development of dysregulated lipolysis and insulin resistance in adipocytes in obesity. Here, PPARG is linked to obesity due to melanocortin 4 receptor deficiency.