As in chronological aging and after serial passage in culture (both of which are associated with increased preadipocyte replicative histories), in obesity adipogenesis, C/EBPα, PPARγ, and their downstream targets are decreased in preadipocytes and fat tissue (Turkenkopf et al., 1988; Shillabeer et al., 1990; Permana et al., 2004; Nair et al., 2005; Dubois et al., 2006; Tchkonia et al., 2006b; Gustafson et al., 2009). This evidence concerns the gene PPARG and obesity due to melanocortin 4 receptor deficiency.