Electron microscopy of cytoplasmic crystalloids in rat parotid glands.

Crystalloid-containing bodies that may be lysosomes were observed by electron microscopy in acinar and striated duct cells of normal fasted rat parotid glands. The crystalloids varied in number from animal to animal and from lobule to lobule. They consisted of either parallel linear densities with a 5Snm periodicity, or of alternating major dense and minor light lines, with a 15 nm distance between successive major lines. it was concluded that the presence of a few such crystalloids in parotid glands of treated rats is not a cytopathic effect and they are significant only when present in large numbers.