Consequently, similar to that previously demonstrated in other endocrine tissues, such as pituitary 31 and mammary gland 40, it has been suggested that the development of obesity could be associated with a certain degree of insulin resistance in the PG and could influence its pathophysiology, modulating the normal expression of several endocrine–metabolic axis, including GH/IGF1/insulin system components, which play a relevant role under normal and pathological conditions. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.