This family consists of several mammalian resistin proteins. Resistin is a 12.5-kDa cysteine-rich secreted polypeptide first reported from rodent adipocytes. It belongs to a multigene family termed RELMs or FIZZ proteins. Plasma resistin levels are significantly increased in both genetically susceptible and high-fat-diet-induced obese mice. Immunoneutralisation of resistin improves hyperglycemia and insulin resistance in high-fat-diet-induced obese mice, while administration of recombinant resistin impairs glucose tolerance and insulin action in normal mice. It has been demonstrated that increases in circulating resistin levels markedly stimulate glucose production in the presence of fixed physiological insulin levels, whereas insulin suppressed resistin expression. It has been suggested that resistin could be a link between obesity and type 2 diabetes.