EVOLUTION OF A CORTICAL COLLECTING TUBULE PRIMARY CULTURE

The evolution of a primary culture of rabbit kidney cortical collectin g duct (CCT) was followed with the electron microscope using two monoc lonal antibodies directed against the principal (Mab 703) and intercal ated (Mab 503) cells, respectively. As a result of the loss of the bas ement membrane surrounding the seeded tubule, the intercalated cells s howed a tendency to be eliminated while the basal cytoplasm of the rem aining cells consisting mainly of principal cells, quickly spread out at the surface of the filter. Between the first and the seventh hour, cells underwent rapid processes of both dedifferentiation and rediffer entiation. At 48 h and later on, they started to proliferate with the production of many multinucleated cells. Normal mitotic divisions, in contrast, were rarely encountered. Whereas the number of intercalated cells as recognized by Mab 503 increased from the fourth day up to the tenth day corresponding to a fully mature culture, culture cells at a ll time intervals rather resembled principal cells found in the intern al part of the cortex or in the outer stripe of the external medulla. It is suggested that in our experimental conditions, dedifferentiated principal cells give rise to both principal and intercalated cells as recognized by immunocytochemistry in the fully developed cell culture.