RBP4 and Insulin resistance: In particular, the adipose tissue, considered as an endocrine organ, produces specific and nonspecific cytokines, including adiponectin (APN), resistin, visfatin, omentin, retinol binding protein-4 (RBP4), lipocalin-2 (LCN2), chemerin, interleukin 6 (IL6), interleukin 1β (IL1β) and tumor necrosis factor α (TNFα), that are able to affect negatively insulin resistance and hormonal release [108].