STK11 and obesity due to melanocortin 4 receptor deficiency: In addition, the Long Evans rats, which exhibit moderate obesity and insulin resistance, were given rosiglitazone and subsequently ameliorated hepatic steatosis which could be modulated by Sirtuin 6 (Sirt6) and its target genes Pparγc1a, forkhead box protein O1 (Foxo1), liver kinase B1 (Lkb1) and 5′ adenosine monophosphate-activated protein kinase (Ampk) [48].