Insulin-Like Growth Factor I (IGF1, Somatomedin C), rat recombinant, (rrIGF1)

Insulin-like growth factor I is the dominant effector of growth hormone and is structurally homologous to proinsulin. Rat IGFI is synthesized as four precursor isoforms with alternate N- and C-terminal propeptides. These isoforms are differentially expressed by various tissues. The 7.6kD mature IGFI is identical between isoforms and is generated by proteolytic removal of the N- and C-terminal regions. Mature rat IGFI shares 96% and 99% aa sequence identity with human and mouse IGFI, respectively, and exhibits cross-species activity. It shares 61% aa sequence identity with mature rat IGFII. Circulating IGFI is produced by hepatocytes, while local IGFI is produced by many other tissues in which it has paracrine effects. IGFI induces the proliferation, migration and differentiation of a wide variety of cell types during development and postnatally. IGFI regulates glucose and fatty acid metabolism, steroid hormone activity and cartilage and bone metabolism. It plays an important role in muscle regeneration and tumor progression. IGFI binds IGFI R, IGFII R, and the insulin receptor, although its effects are mediated primarily by IGFI R. Heterodimers of insulin receptor/IGFI R also exist and respond to IGFI but not to insulin stimulation. IGFI association with IGF binding proteins increases its plasma half-life and modulates its interactions with receptors. Activity: Measured by its ability to induce proliferation of MCF-7, a human breast carcinoma cell line, under serum free conditions. The ED50 for this effect is typically 0.6-3ng/ml. Endotoxin: <1EU/ug (LAL) , N-Terminal Sequence Analysis: Met, Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.