1988 Volume 156 Issue 4 Pages 417-418
Ultrastructural behavior of fusiform vesicles with an asymmetrical unit membrane in the rat transitional epithelium was investigated by in situ injection of gold colloidal particles and gold-labeled Ricinus communis lectin, and by section staining with the lectin. These experiments suggest that the fusiform vesicles are not formed from the luminal cell membrane by contraction of the urinary bladder, and that old luminal cell membranes are removed via multivesicular bodies.