The mucus layer covering the surface epithelium of gastric mucosa consists of glycoproteins, proteins and lipids in the form of a gel imbibed with water and electrolytes. Although the ability of gastric mucus to retard diffusion of H+ has been demonstrated, the role of its glycoprotein and lipid components in this process remains undefined. In this study, utilizing the sintered glass barrier technique, we have measured the diffusion rate of H+ through the unstirred layer of mucus glycoproteins in their native, degraded and delipidated forms. While the rate of H+ diffusion through the unstirred layer of undegraded mucus glycoproteins and the native mucus was similar, a decrease of over 70% in H+ retardation was obtained following digestion of the purified glycoprotein with pronase or pepsin. However, the delay of H+ diffusion was not completely abolished by proteolysis. Increased permeability of mucus glycoproteins to H+ was also observed following their delipidation. Reassociation of the delipidated glycoproteins with their lipids resulted in a complete restoration of the retardation of H+ diffusion. These results point toward the involvement of mucus glycoproteins and lipids in retardation of H+ diffusion by gastric mucus.
|Original language||English (US)|
|Number of pages||1|
|Journal||IRCS Medical Science|
|State||Published - 1983|
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)