The link between obesity and diabetes is strong as well as complex. Fat cells produce many circulating regulators of insulin sensitivity, including pro-inflammatory cytokines. In rodents, resistin is produced by adipose tissue, and is a significant regulator of glucose metabolism and insulin sensitivity. In humans, resistin is derived made mainly from macrophages. Given the emerging interrelationship between inflammation and metabolic disease, hyperresistinemia may be a biomarker, and/or a mediator, of metabolic and inflammatory diseases in humans as well as in rodents.