Quantitative three-dimensional reconstruction and carbohydrate cytochemistry of rat nonciliated bronchiolar (Clara) cells.

Journal Article (Journal Article)

We have employed three-dimensional reconstructions and cytochemistry to analyze nonciliated bronchiolar epithelial (Clara) cells from rat lungs. We identified a previously unreported ovoid granule type, which was characterized by its relative electron-lucency and eccentric electron-dense core. These electron-lucent granules were less common than electron-dense granules and were polarized toward the Golgi. They occupied 0.51% of the cell volume. Quantitative analysis of cell volume fractions showed the more numerous electron-dense granules to be polarized toward the air border; they occupied 2.5% of the cell volume. Periodic acid-thiocarbohydrazide-silver protein staining for hexose sugars indicated no differences between the granule types with regard to their carbohydrate content. Multivesicular bodies occupied 0.42% of total cell volume and were distinctly polarized toward the surface of the Golgi. Rod-shaped granules were present in 4 of the 6 reconstructed cells, ranging in number from 0 to 9 per cell. Nine apparent secretory events were seen in 6 cells and all appeared as exocytosis. We conclude that rat Clara cells contain at least 3 morphologically distinct granule types located in different volumes of the cell, and that exocytosis is the mode of secretion. The functional relationship between the ovoid granule types could include precursor-product lineage or different secretory products. We suggest that multivesicular bodies and light granules are stages in dark granule genesis.

Full Text

Duke Authors

Cited Authors

  • Young, SL; Fram, EK; Randell, SH

Published Date

  • May 1, 1986

Published In

Volume / Issue

  • 133 / 5

Start / End Page

  • 899 - 907

PubMed ID

  • 3706901

International Standard Serial Number (ISSN)

  • 0003-0805


  • eng

Conference Location

  • United States