Zafirovic et al., ( 24 ) showed that obesity, in addition to hindering glucose uptake and insulin signaling in the heart, elevates the production of NO in the heart through the increase in the expression of inducible nitric oxide synthase (iNOS) ( 24 ) Nitric oxide is an important vasodilator and directly influences cardiac contractility. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.