Insulin-like growth factor-I: Marker for diagnosis of acromegaly and monitoring the efficacy of treatment

Abstract

Acromegaly is caused by chronic excess secretion of growth hormone (GH) and resultant persistent elevation in concentrations of insulin-like growth factor-I (IGF-I), also called somatomedin-C. A number of diagnostic tests are available to support the diagnosis of acromegaly, but those that rely on measurement of serum GH concentrations have important limitations. Concentrations of serum IGF-I, which is produced principally in the liver and mediates the actions of GH, have been shown to correlate with clinical and metabolic markers of disease activity. Additionally, normalisation of IGF-I levels in acromegaly is associated with the resolution of symptoms and normal life expectancy. Thus, serum IGF-I is an important marker of disease activity and a sensitive, practical, and reliable measure of integrated GH concentrations in patients with acromegaly.