IGF-2 is a member of the insulin family of polypeptide growth factors that is involved in development and growth. It is an imprinted gene and is expressed only from the paternally inherited allele. It is a candidate gene for eating disorders. There is a read-through, INS-IGF2, which aligns to this gene at the 3' region and to the upstream INS gene at the 5' region. Two alternatively spliced transcript variants encoding the same protein have been found for this gene.
IGF1-LR3 is a modified version of insulin-like growth factor-1. The full name of the peptide is insulin-like growth factor-1 long arginine 3. All IGF-1 derivatives play prominent roles in cell division, cell proliferation, and cell-to-cell communication. Though it has similar effects, IGF-1 LR3 does not adhere to IGF binding proteins as strongly as IGF-1. This results in IGF1-LR3 remaining in the bloodstream 120 times longer than IGF-1. IGF1-LR3 gains its prolonged half-life as a result of its structural changes. The peptide is created by adding 13 amino acids to the N-terminal end of IGF-1 and by converting the glutamic acid at position 3 of IGF-1 to an arginine residue.