In addition to its role as an incretin GLP-1 (glucagon-like peptide-1) and GIP (gastric inhibitory polypeptide) inhibitor, this protein has recently been identified as an adipokine released to a greater extent by visceral adipose tissue, and, in particular, in obese and insulin-resistant patients, and has, therefore, been suggested as a biomarker of visceral obesity, insulin resistance, and metabolic syndrome [86]. This evidence concerns the gene GCG and Insulin resistance.