LIPID COMPOSITION OF BRUSH BORDERS OF RAT INTESTINAL EPITHELIAL CELLS

The lipid composition of brush border organelles isolated from the mucosa of rat small intestine has been investigated. The phospholipid: cholesterol ratio found was higher than that previously reported for purified microvillus membranes. Differences in the phospholipid: protein ratio when alternative techniques were used indicated that part of the lipid was more difficult to remove and that this part constituted perhaps as much as 50% of the total lipid. The lipids removed, however, remained in approximately the same proportion. Thus no differential solubility factor was indicated. The principal lipids were phosphatidyl ethanolamine (40%), phosphatidyl choline (30%) a and the combined phosphatidyl inositol and phosphatidyl-serine (20%). © 1968.