In contrast to our results, one study has found that hepatic p38 MAPK activation, via adenoviral-mediated overexpression of MAPK kinase 6, in ob/ob mice is beneficial to insulin sensitivity.15 Our results support the results by another group that using adenoviral-mediated overexpression of dominant-negative p38α MAPK found improved glucose tolerance and reduced hyperinsulinemia and PEPCK expression in ob/ob mice.5 Here, PCK2 is linked to hyperinsulinism.