In this work we characterized the histopathological manifestations of obesity –induced renal injury in obese Zucker (ZO) rats; and investigated the urinary enzymatic activities of AlaAp and GluAp, plasma, urinary and renal Klotho levels and urinary and renal hydroxyproline as potential biomarkers of the renal injury observed in ZO rats. The gene discussed is KL; the disease is obesity due to melanocortin 4 receptor deficiency.