[Intracisternal granules in the parotid gland of the rat]

The present paper describes electron-dense accumulations of the secretory product in dilated cisternal spaces of the granular endoplasmic reticulum in the exocrine secretory cells of the parotid gland of the rat. These are called intracisternal granules. Electron microscopic observations elucidated the localization and morphology of the intracisternal granules: 1. Predominant localization in the granular endoplasmic reticulum of the basal part of the cells. 2. Main morphological features: spheric, electron-dense granules of variable size (50-300 nm) without limiting membrane.