We studied long-term MC4R deficiency on rats using the autoimmune model; the animals were immunized with BSA-conjugate of peptide K-[TSLHLWNRSSHGLHG11–25]-A corresponding to the region 11–25 of the N-terminal portion of MC4R. Nine–thirteen months after the first immunization the animals had weight gain, impaired glucose tolerance, insulin resistance and dyslipidemia. This evidence concerns the gene MC4R and Impaired glucose tolerance.