IGF-1
IGF-1
IGF-I is an important hormone for human development. Its levels are especially high during childhood and adolescence, where it supports linear growth, as well as the growth of nearly all body tissues. Serum IGF-I levels decline greatly in adulthood, though remain substantial throughout life. This hormone will continue to play important roles in metabolism and physiology, including the support of skeletal muscle mass and strength. IGF-I has several key anabolic/anti-catabolic activities. It supports the synthesis of new muscle protein, satellite cell activity, and the incorporation of new nuclei into muscle cells. It is also noted for reducing the activity of both p27Kip1 and myostatin, which are two powerful inhibitors of muscle growth. As such, IGF-I is regarded as possessing both strong anabolic and anti-catabolic properties.