To create the model of MC3R deficiency, rats were immunized with BSA-conjugate of peptide A-[PTNPYCICTTAH269–280]-A corresponding to the third extracellular loop of MC3R, and 13 months later the immunized animals had dyslipidemia, decreased body weight, but increased mass of abdominal fat, which indicated changes in the fat/muscle weight ratio and abnormalities in the lipid metabolism [240]. This evidence concerns the gene MC3R and metabolic syndrome.