Molecular mechanisms of insulin resistance

This review discusses recent advances in understanding of the structure and function of the insulin receptor and insulin action, and how these relate to the clinical aspects of insulin resistance associated with non-insulin-dependent diabetes and other disorders. Improved understanding of the molecular basis of insulin resistance could ultimately lead to a better understanding of the causation of these conditions and the design of rational therapy to ameliorate them. Here, particular attention is devoted to the initial events that follow the binding of insulin to its receptor, including changes in insulin receptor phosphorylation. Receptor-mediated insulin resistance may be a consequence of various factors including increased serine/threonine phosphorylation of the receptor with decreased tyrosine phosphorylation, receptor densitisation, auto-antibodies to the receptor and inherited structural defects in the insulin receptor. Defects in insulin action could also arise at post-receptor events particularly glucose transport. Other circulating hormones, such as the newly characterised islet amyloid polypeptide (amylin), may also cause insulin resistance.