Some of their important functions, exerted mainly through the action of adenosine on A1 receptors, concern the inhibition of lipolysis and the reduction of free fatty acids (whose involvement in the pathogenesis of insulin resistance, diabetes, cardiovascular diseases is recognized), the reduction in insulin resistance is associated with obesity, the increase in leptin production (with an additional beneficial effect on insulin sensitivity), and the increase in the uptake of glucose by adipocytes (with improvement of glucose tolerance but also in triglycerides storage and weigh gain). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.