ABSTRACT
Resistance to insulin was first described more than 60 years ago, when
some patients with diabetes were noted to be less sensitive to insulin
treatment than others.1 The development of the radioimmunoassay
(RIA) technique for the measurement of insulin by Berson and Yalow
started the modern study of insulin resistance in man. Insulin resis-
tance describes an impaired biological response to insulin.2 It has
been broadly defined as ‘a state (of a cell, tissue, or organism) in
which a greater than normal amount of insulin is required to elicit a
quantitatively normal response’.3,4 However, insulin resistance can be
selective – i.e. involving only certain aspects of insulin action – a fact
that complicates both the definition and its characterization in vivo
and in vitro.5 This chapter will focus on the clinical effects of insulin
resistance on type 1 diabetes, its role in obesity and type 2 diabetes,
and possible ways of modifying insulin resistance. The underlying
pathophysiology of insulin resistance and in-vivo assessment of
insulin sensitivity will also be discussed.