Role of Adiponectin and Inflammation in Insulin Resistance of Mc3r and Mc4r Knockout Mice

Abstract

Our findings suggest that severe insulin resistance of Mc4rKO fed a HFD, as reported in other models of obesity such as leptin-deficient (Lep(ob)/Lep(ob)) and KK-A(y) mice, is linked to reduced serum adiponectin and high levels of inflammation in adipose tissue. Conversely, maintenance of normal serum adiponectin may be a factor in the relatively mild insulin-resistant phenotype of severely obese Mc3rKO. Mc3rKO are, thus, a unique mouse model where obesity is not associated with reduced serum adiponectin levels. A delay in macrophage infiltration of adipose tissue of Mc3rKO during exposure to HFD may also be a factor contributing to the mild insulin resistance in this model.