DYNAMIC STRUCTURE OF GOLGI APPARATUS DEPENDING UPON FUNCTIONAL PHASES OF SECRETION

Ultrastructural changes in Golgi apparatus (GA) during various functional conditions were studied in the rat parotid glands, and their three dimensional configuration was analyzed with the use of computer graphics from serial section electron micrographs. Three dimensional reconstruction confirmed that a normal GA was a connected single structure located in the supranuclear region, although it exhibited markedly complicated and reticulated branches. In contrast when host cells entered into the mitotic phase, underwent postnatal development and were inhibited of transport of secretory materials from rough endoplasmic reticulum, GA became an aggrega-tion of small vesicles or tubules, in which cis and most likely medial, but not trans elements were included. From these observations, we propose a new hypothesis that a GA consists of two components, basic and functional ones. The basic component having small vesicles and tubules of cis and medial natures is the most primitive feature of GA that is recognized in such cellular phases as early development, mitosis, and interruption of inflow. Basic components evolve a functional one that consists of a lamellar structure with cis, medial and trans elements. They are recognized in the usual cells at the active states. The size and overall configuration of GA changes greatly due to the amount of inflow of secretory materials depending upon the functional conditions of the cells.