Mucous glycoproteins from cat tracheal goblet cells and mucous glands separated with EDTA.

Respiratory tract mucous glycoproteins (MGP) are secreted by goblet cells in the surface epithelium and by submucosal glands. The MGP in airway secretions collected in vivo and from airway explants in vitro represent an admixture of secretions from these sources. Incubation of cat tracheal explants in 20 mM EDTA allowed physical separation of the surface epithelium from the underlying tissues and the culture of each isolated secretory element. Separated tissues appeared morphologically intact and continued to secrete MGP. The MGP arising from the surface epithelium had more sialic acid relative to galactose and N-acetylglucosamine and appeared to be less highly sulfated, as determined by DEAE cellulose chromatography, than MGP from submucosal glands. The EDTA-mediated separation of the airway secretory elements may allow further investigation into specific secretory functions of these two epithelial elements.