ELECTRON MICROSCOPIC STUDY OF APOCRINE SECRETION

[摘要] Two types of granules were seen in the secretory cells of apocrine glands, dark granules which formed initially from the Golgi apparatus and light granules which appeared to be the modified mitochondria. The formation of a secretory projection at the luminal, or apical, portion of the cell appeared to be the 1st stage of apocrine secretion. Although the cytoplasm of the secretory projection possessed few or no organelles, dark granules accumulated in large numbers in the cytoplasm beneath the secretory projection. There seemed to be 2 major types of secretory processes; one type concerned with a slow, gradual secretion and involved formation of pinched-off villi with the escape of small vesicles, or a defect formation in the plasma membrane with subsequent release of the contents; in some instances, instead of merely spilling its cytoplasmic contents into the lumen, the entire apical secretory projection sheared off or decapitated. The 2nd type involved a massive destruction of the dark secretory granules, probably a rapid process and presumably in response to strong stimuli; this process resulted in an excavation of the entire cytoplasmic content of the cell into the lumen. The types of enzymes as well as the morphology and the behavior of the dark granules suggest that the large dark granules are lysosomes.