[Ultrastructural studies on the permeability of the amnion-epithelium for peroxidase and ferritin. Contribution on paraplacental metabolism].

By means tracer substances (horseradish peroxidase, ferritin) the permeability of human amnion and umbilical cord (2. to 6. lunar month) has been investigated ultrastructurally. The structure of intercellular cleft permits a passiv transfer of the water and electrolytes in both ways. The findings indicated, that the passage of proteins with a molecular weight of peroxidase predominantly takes place through the intercellular clefts less by means of pinocytosis. Ferritin particles can not penetrate. The epithelium of umbilical cord seems to play no special role in protein and water transport. The results were discussed.