In view of the morphological and physiological complexity of the mammalian epididymis, the aim of the present ultrastructural study was to identify cytoplasmic sites containing cisternae of the Golgi apparatus in epididymal principal cells of the dog.
The most notable characteristic of the supranuclear region of dog epididymal principal cells was the presence of the Golgi apparatus, detected by the ZIO method, which consisted of numerous cisternae and vesicular elements of variable size, occupying most of the supranuclear cytoplasm (Figs.
The cisternae were stacked and formed the so-called compact zone of the Golgi apparatus.
On the cis side of the Golgi apparatus some small vesicles, transport or transfer vesicles, could be observed, which seemed to originate from the endoplasmic reticulum and to be incorporated into the cisternae on the cis side of the sack (Figs.
Two types of endoplasmic reticulum cisternae could be differentiated: the first type was generally flattened, although slightly distended, and contained granulofilamentous material.