NOS2 and obesity due to melanocortin 4 receptor deficiency: Obesity-related enlargement of adipocytes is associated with an increase in free fatty acids (FFA) release and the production of several pro-inflammatory factors [7], including tumor necrosis factor-alpha (TNF-α) [8,9], interleukin 6 (IL-6), monocyte chemotactic protein 1 (MCP-1), inducible nitric oxide synthase (iNOS), and transforming growth factor–beta 1 (TGF-β1) [7,10,11].