The insulin-like growth factors-I and -II (IGFs) are involved in a wide array of cellular processes such as proliferation, prevention of apoptosis, and differentiation. Most of these effects are mediated by the IGF-I receptor, although at higher IGF concentrations the insulin receptor can also be activated. As the expression of both the IGFs and their receptors is widespread, IGFs are thought to have autocrine/paracrine modes of actions also, particularly during foetal life.
