PTGS2 and obesity due to melanocortin 4 receptor deficiency: It is known that (pre)adipocytes, a predominant cell type present in the adipose tissues, express and secrete a variety of adipokines (leptin, adiponectin, etc.)as well as inflammatory cytokines (TNF-α, IL-1β, IL-6, etc.)and enzymes (iNOS, COX-2, etc.)[23], which confer obesity inflammation.