Isolation of a somatomedin binding protein from human preterm amniotic fluid : development of a radioimmunoassay

This thesis study was undertaken in order to investigate the nature and biological behavior of a somatornedin binding protein, identified in preterrn amniotic fluid (AF). Somatomedin (SM) is the generic designation applied to a family of serum peptide growth factors which are growth hormone dependent, stimulate incorporation of sulphate into cartilage, have insulin-like actions on nonskeletal tissues and increase mitosis in a wide variety of cultured cells. Thusfar two peptides have been fully characterized: insulin-like growth factor I (IGF-I), shown to be identical to sornatomedin-C, and insulin-like growth factor II (IGF-II). IGF-I and IGF-II have a 62% aminoacid sequence identity and are 38-48% homologous with the A and B domains of human pro-insulin.