Ultrastructural study on nuclear bodies of the rat parotid glands.

Nuclear bodies of types I, II, III and IV are constantly present in rat parotid glands. They become apparent on the 21st day and afterwards. Type IV nuclear bodies were chiefly found in the striated ducts. Nuclei containing 3 and more nuclear bodies were found as early as the 3rd month, although only in the striated ducts. Nuclear bodies are not related to glycogen or DNA replication but probably to rRNA metabolism. This study leads to a better understanding of nuclear bodies modifications which can be observed ultrastructurally in human salivary glands pathology. Their increased number in some nuclei may be the expression of an alteration of the cell metabolism.