Although all these data indicate that the adipocytes appear to be the major source of elevated IL-6, IL-8, and MCP-1 levels observed in obesity (Shimomura et al., 1996; Morange et al., 1999), it is still a matter of debate whether this is a result of stimulation of adipocytes via direct cell contacts with macrophages or an effect caused by hormones and cytokines released from the macrophages (Loskutoff and Samad, 1998). This evidence concerns the gene CCL2 and obesity due to melanocortin 4 receptor deficiency.