Submucosal mucous glands

Slomiany et al. (45) reported the lipid and protein composition in tracheobronchial secretions from normal individuals and patients with cystic fibrosis. In the normal bronehial secretions, the total phospholipid was only about half as mueh as has been reported for normal alveolar surfactant (46). The largest differ-enees were in the amounts of lysophosphatidylcholine, 29.5 versus 0.4%, sphingomyelin, 15.8 versus 3.7%, and phosphatidylethanolamine, 12.4 versus 2.6%, respectively. The differences in the surfactant composition between alveolar and airway surfaetant may be due to the addition of mucus from goblet cells and submucosal mucous glands (47), and the contribution of Clara cells (48). 

Cat tracheal epithelial goblet cells did not show any immunoreactivity for cyclic AMP, while both serous and mucous cells in submucosal glands immunore-active cyclic AMP (Lazarus et al. 1984). 

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