IGF-1 (Insulin-like Growth Factor)

General Information

Insulin-like growth factor - 1 (IGF-1) has sequence similarity to insulin, and similar biological functions as insulin e.g. inhibits lipolysis, increases glucose oxidation in adipose tissues. Other functions include growth-promoting effects on cartilage and enhanced synthesis of proteoglycans and collagen. IGF-1 levels normally are low in early childhood, increase gradually during childhood, peak during puberty, and then decline in adult life. The IGF-1 test is an indirect measure of the average amount of growth hormone (GH) being produced by the body. The concentration of IGF-1 is stable throughout the day, making it a useful indicator of average GH levels (as GH has pulsatile secretion).

Patient Preparation

None

Notes

IGF-1 is measured to help diagnose the cause of growth abnormalities and to evaluate pituitary function. (Formerly known as somatomedin)

IGF-1 concentrations are high in states of Growth Hormone excess and low in states of Growth Hormone deficiency.

Serum levels of IGF-1 are also low in patients with acute or chronic protein or calorie deprivation.