It was recently reported that SREBPs are essential for hepatic steatosis in dietary and genetic rodent models of obesity [28], suggesting that a high level of SREBP-1c in high-fat diet-induced obese rats up-regulates the expression of FAS and ACC1 and subsequently increases lipid synthesis, which may be associated with increased insulin levels in obese rats. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.