Three-dimensional ultrastructure of the Golgi apparatus in different cells: high-resolution scanning electron microscopy of osmium-macerated tissues.

The three-dimensional ultrastructure of the Golgi apparatus in different cells of the rat - epithelial principal cells in the epididymal duct, goblet cells in the jejunum, gonadotrophs in the pituitary gland and dorsal root ganglion cells - was studied by scanning electron microscopy (SEM) of osmium-macerated tissues. The Golgi apparatus in the epididymal principal cells took the shape of a candle flame with irregular-shaped cisterns, while those in the goblet cells of the jejunum were cup-shaped or cylindrical with flat cisterns. Gonadotrophs had a large spherical Golgi apparatus; this apparatus was composed of several concentric cisterns with large round windows through which the rough endoplasmic reticulum (rER) and mitochondria extended into the center of the globular Golgi apparatus. Dorsal root ganglion cells had several small Golgi stacks scattered in the cytoplasm. In all Golgi apparatuses of the different cells examined in the present study, the cis-most cistern was generally composed of a flattened sheet with numerous small fenestrations on its wall. On the other hand, the shape of the trans-most cistern varied by cell type; it was generally composed of tubules and/or small sheets which were sometimes connected with each other to form a rather complicated structure. The cis-most cistern and the trans-most cistern were often closely associated with the rER although no direct communication was found between them. These findings indicate that the structure of the Golgi apparatus, especially its overall shape and the ultrastructure of the trans-most cistern, varies by cell type, a point to be considered in relation to the function of the individual cells.