rec. Human Insulin-Like Growth Factor I (rHulGF-I)

The somatomedins, or insulin-like growth factors (IGFs), comprise a family of peptides that play important roles in mammalian growth and development. IGF1 mediates many of the growth-promoting effects of growth hormone (GH, MIM 139250). Early studies showed that growth hormone did not directly stimulate the incorporation of sulfate into cartilage, but rather acted through a serum factor, termed 'sulfation factor,' which later became known as 'somatomedin' (Daughaday et al., 1972). Three main somatomedins have been characterized: somatomedin C (IGF1), somatomedin A (IGF2, MIM 147470), and somatomedin B (MIM 193190) (Rotwein, 1986, Rosenfeld, 2003). The ED50, calculated by the dose-dependant proliferation of murine BALB\C 3T3 cells (measured by 3H-thymidine uptake) is 1.0ng/mL, corresponding to a specific activity of 1 x 10(6) U/mg. For most in-vitro applications, IGF-I exerts its biological activity in the concentration range of 0.2-20ng/mL.