Morphology of epithelio-mesenchymal interaction during lung development of the mouse.

Basement membrane gaps and epithelio-mesenchymal contacts could be shown in the lung of mouse embryos during the entire pregnancy period. Some of the contacts corresponded to gap junctions. The significance of these findings for the differentiation of epithelium and mesenchyme, as well as for the development of the epithelial tube system of the lung as a model for the epithelio-mesenchymal interaction, has been discussed taking into account the results of other investigators. It was concluded that direct epithelio-mesenchymal contacts are necessary for organ development.