Insulin-like Growth Factor - Diseases Affected By IGF

Diseases Affected By IGF

Studies of recent interest show that the Insulin/IGF axis play an important role in aging. Nematodes, fruit-flies and other organisms have an increased life span when the gene equivalent to the mammalian insulin is knocked out. It is somewhat difficult to relate this finding to the mammal, however, because in the smaller organism there are many genes (at least 37 in the nematode) that are "insulin-like" or "IGF-1-like", whereas in the mammals insulin-like proteins comprise only seven members (insulin, IGFs, relaxins, EPIL, and relaxin-like factor) and have apparently distinct roles with some but less crosstalk. On the other hand, simpler organisms typically have fewer receptors (only one known in the nematode) and the roles of these other insulins are unknown. Furthermore these animals do not have specialized organs (Islets of Langerhans), which sense insulin in response to glucose homeostasis. Therefore it is an open question as to whether either IGF-1 or insulin in the mammal may perturb aging, although there is strong suggestion dietary restriction phenomena are related.

Other studies are beginning to uncover the important role the IGFs play in diseases such as cancer and diabetes, showing for instance that IGF-1 stimulates growth of both prostate and breast cancer cells. Researchers are not in complete agreement about the degree of cancer risk that IGF-1 poses.