Since obesity-linked insulin resistance may be associated with dysfunctional adipocytes (Friedman and Haalas, 1998; Steppan et al., 2001; Galic et al., 2010; Ouchi et al., 2011), we concentrated on adipocytes for further analysis of the NCS-1−/− phenotype. The gene discussed is NCS1; the disease is obesity due to melanocortin 4 receptor deficiency.