GCG and obesity due to melanocortin 4 receptor deficiency: The role of IL-6 in muscle metabolism is further elucidated by the recent report that IL-6 stimulate insulin secretion via GLP-1 induction [11], suggesting that the increased levels of IL-6 associated with obesity and insulin resistance might be a compensatory mechanism (i.e. an increased IL-6 production is initiated to induce more insulin).