INS and obesity due to melanocortin 4 receptor deficiency: Whereas some studies have demonstrated that macrophages accumulate in tissues other than adipose during obesity, including skeletal muscle ((Fink et al., 2013, Hevener et al., 2007, Nguyen et al., 2007); NAT, CWJ and MEC, unpublished data) little attention has been paid to the potential impact of this upon muscle insulin sensitivity.