Insulin Like Growth Factor 1(IGF-1)

An indirect measure of the average amount of growth hormone (GH) being produced by the body. This insulin-like growth factor level is used to evaluate disturbances of growth and to monitor treatment with growth hormones.

The primary source of circulating IGF-1 is from the liver, although many tissues synthesize IGF-1. Circulating IGF-1 increases insulin sensitivity.  Reduced levels are associated with insulin resistance, a risk for subsequent development of impaired glucose, or type 2 diabetes. (Tietz Clinical Guide to Laboratory Tests 4th ed. edited by Alan H.B. Wu. 2006.)

Chemical interferences and in-vivo effects: High doses of estrogen administration  can decrease IGF-1 levels. Androgenic progestins oppose the estrogen-induced IGFBP-1 increase. (Tietz Clinical Guide to Laboratory Tests 4th ed. edited by Alan H.B. Wu. 2006.)