INS and Insulin resistance: Although suppression of endogenous glucose production by insulin is a well-established indicator to discriminate hepatic insulin resistance from extra-hepatic origins using a euglycemic-hyperinsulinemic clamp test, phosphorylation of Akt is also a sensitive and convenient indicator of insulin signaling under physiological conditions (Saltiel and Kahn, 2001; Whiteman et al., 2002).