PPARG and obesity due to melanocortin 4 receptor deficiency: These effects were attributed to a reduced expression of peroxisome proliferator-activated receptor (PPAR)γ and CCAAT-enhancer-binding protein (C/EBP)α, which are major transcription factors required for adipogenesis.(12–15) Besides these in vitro findings, the administration of rapamycin to rodents in vivo was associated with a reduction in adiposity due to lower expression of PPARγ and target genes involved in lipid uptake and storage(16) and a protection against the fat mass expansion and obesity induced by the intake of a high-fat diet.(17)