Parotid acinar cell contains many secretory granules. Most of granules are mature, but only little immature granules are included. These immature granules are not enough for investigation of granule maturation. In this study, we show an easy method of separation of immature granules from the rat parotid gland. In addition, we succeeded in detection of color dye in the granules. These results suggest that secretory granules can be visualized through endocytosis
