Possible biogenesis of the membrane-bound bodies of the thick basal laminae of the proximal convoluted tubule cells of the gerbil Meriones crassus.

The ultrastructural findings on the kidney cells of the gerbil Meriones crassus have shown the presence of finger-like projections emerging from the basal part of the epithelial cells of the proximal convoluted tubules into the matrix of the thick basal laminae and that structure like membrane-bound bodies are commonly seen in continuity with these processes. Such findings would give clues for the possible biogenesis of the membrane-bound bodies from the epithelial cells. Such an origin is consistent with the idea that either all or part of the population of membrane-bound bodies is produced by a process of budding off from the basal cell membrane rather than by extension of an intracytoplasmic precursor through the plasma membrane.