Insulin-like Growth Factor-2, also known as somatomedin A, is an important growth factor released by the liver in response to growth hormone. IGF-2 has been found to be an important modulator of muscle growth, helping to stimulate the maturation of dormant new muscle cells. It is also involved in the health of the brain, nerves, liver and kidneys. IGF-2 is also a mitogen for many types of normal cells. More information about the body's growth factors.