Expression of the insulin-like growth factor receptor 1 during human embryogenesis.

Insulin-like growth factor 1 and its receptor (IGF-1/IGF-2) may play important roles in the development of human fetal tissue, and its ligands IGF-1 and IGF-2 have been found in fetuses older than 3 months. Our objective was to study the immunohistochemical distribution of IGF 1-R in tissues obtained from human normal embryos following abortion or natural termination of pregnancy. Immunohistochemical staining was performed on autostainer, using an anti-IGF1-R rabbit polyclonal antibody (dilution 1:75), and the avidin-biotin peroxidase complex method. The embryos ranged between 28 days to 8 weeks gestation. Fully 3 cases were 28 days old, 1 case 32 days old, 2 cases 6 weeks old and 2 cases 8 weeks old. The IGF1-R stain decorated the surface ectoderm, the optic cup, and the lens placode, pharynx, respiratory diverticulum, foregut, liver cords, mesonephros, and metanephric blastema. Mesodermal structures, including limb mesoderm, and neural crest derivatives were IGF-1R negative. On study shows the preferential IGF-1R immunolocalizatrion in specific areas of the developing embryo, suggesting a role of IGF1-R for the optimal maturation of those areas, during developing human embryos.