in this report we describe the discovery of a novel , more potent , form of igf-1 , des- ( 1-3 ) -igf-1 , and explain its increased action as resulting from higher concentrations of the free peptide produced because des- ( 1-3 ) -igf-1 binds very poorly to igf carrier proteins released from most cell types .
C0021665
igf-1
C0037657
igf