In order to evaluate the possibility that MKP-2 regulates the expression and secretion of cytokines, cell–cell signaling proteins that systemically control the progression of obesity, and development of insulin resistance and hepatic steatosis, we performed a mouse cytokine antibody array to analyze for the levels of 96 mouse proteins in blood serum of HFD-fed Mkp-2+/+ and Mkp-2−/− mice. Here, DUSP4 is linked to obesity due to melanocortin 4 receptor deficiency.