Diabetic KK-A [52], leptin-resistant (db/db) [53, 54] and leptin-deficient (ob/ob) [55, 56], high fat [9] and high fructose [57] diet-fed mice all of which exhibit hepatic steatosis, have all been reported to demonstrate impeded regeneration after hepatectomy or CCL4 administration. This evidence concerns the gene LEP and fatty liver disease.