Lipid composition of the gastric mucous barrier in the rat

The lipid composition of the "mucous barrier" of rat stomach was investigated. Cellular mucus of the mucous cells from gastric epithelium and surface mucus from gastric mucosa were obtained by perfusion in vivo of Ghosh-Lai rat stomachs with 2 M NaCl. Lipids extracted from dialyzed and lyophilized 2 M NaCl perfusates and 0.9% NaCl (saline) controls were quantitatively separated into single components by means of two-dimensional thin layer chromatography and compared. Significant differences in the level of cholesterol esters, di- and triglycerides, and glycolipids were found. Three to 4 times greater quantities of cholesterol esters and di- and triglycerides, and 2 to 6 times greater quantities of glycolipids were found in 2 M NaCl perfusates as compared to saline controls. The glycolipid fraction consisted of neutral and acidic glyceroglucolipids and was devoid of glycosphingolipids. The phospholipids constituted the smallest portion of the lipids present in 2 M NaCl and saline perfusates and were 2 times higher in 2 M NaCl. These data indicate that mucous barrier in addition to mucins contains considerable quantities of lipids of which glyceroglucolipids are the most prominent components.