Phospholipids and cholesterol in brush border and basolateral membranes from rat intestinal mucosa

Total phospholipids and free cholesterol reach higher levels in basolateral membranes than in brush border membranes, these membranes being purified from rat intestinal mucosa. Cholesterol/phospholipid and cholesterol/phospholipid choline molar ratios are lower in basolateral membranes. Lysophosphatidylcholine, sphingomyelin and phosphatidylinositol are approximately twice as high in brush border membranes (respectively, 8.7, 24.1 and 22.3% total lipid phosphorus) when compared to basolateral membranes (respectively, 3.6, 12.5 and 11.5% total lipid phosphorus). Conversely, basolateral membranes are richer than brush border membranes in phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and diphosphatidylglycerol (basolateral membranes: 36.9, 8.1, 24.8, 1.7% total lipid phosphorus; brush border membranes: 26.7, 4.4, 11.9, 0.5% total lipid phosphorus.