Insulin-like growth factor 2 (IGF-2) is one of three protein hormones that share structural similarity to insulin. IGF-2 is a well-characterized neutral peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on somatotropin. It is believed to be a major fetal growth factor in contrast to Insulin-like growth factor 1, which is a major growth factor in adults”.

It is sometimes produced in excess in islet cell tumors, causing hypoglycemia. Doege-Potter syndrome is a paraneoplastic syndrome in which hypoglycemia is associated with the presence of one or more non-islet fibrous tumors in the pleural cavity. Loss of imprinting of IGF2 is a common feature in tumors seen in Beckwith-Wiedemann syndrome. As IGF2 promotes development of fetal pancreatic beta cells, it is believed to be related to some forms of diabetes mellitus. Preeclampsia induces a decrease in methylation level at IGF2 demethylated region, and this might be among the mechanisms behind the association between intrauterine exposure to preeclampsia and high risk for metabolic diseases in the later life of the infants.