A COMPARATIVE STUDY OF THE GOLGI COMPLEX

The ultrastructure of the Golgi complex has now been described in detail in a variety of cells of vertebrates (1-10) and in a few invertebrates (11, 12). I t is apparent that the original description of the complex as consisting of a system of smooth membranes, small granules or vesicles, and large vacuoles (1) holds for many cell types, particularly those epithelial cells concerned primarily with absorptive and/or secretory activity (13). In certain cases the large vacuoles are greatly reduced in size or entirely absent (10, 13). The complex has been described in cells of the central nervous system and referred to as the "agranular reficulum" (10). Evidence has also been presented which indicates that, in some instances at least, the membranes of the ergastoplasm (endoplasmic reticulum) are in continuity with the membranes of the Golgi complex (14). A comparison will be made of the ultrastructure of the Golgi complex in a series of cell types, one primarily secretory, one primarily absorptive, one thought to be both secretory and absorptive in function, and one in the process of differentiation. I t is suggested that the comparison demonstrates a basic and characteristic similarity of ultrastructure which supports the concept of the complex as a morphologic entity distinct from other cell components. I t is felt that this is true even though the membranes of the complex and of the ergastoplasm may at times be in continuity with one another. In addition it will be demonstrated that certain components of the Golgi complex react in a markedly different way from other intracellular structures on secondary treatment with osmic acid.