• rat intestine;
  • lasting;
  • brush border membranes;
  • freeze-fracture;
  • cholesterol;
  • protein phospholipid ratio

The densities of intramembranous particles (IMPs) and of sterol complexes induced by treatment of filipin were studied by freeze-fracture replication of intact intestine and/or isolated brush border membranes (BBM) of well-fed and starved rats. The density of IMPs and filipin-sterol complexes (FSCs) decrease considerably during starvation. Biochemical estimations show a decrease in the levels of cholesterol and proteins with respect to phospholipids during starvation which is in agreement with morphological findings. It is suggested that these changes may play a role in regulating membrane fluidity which in turn affects absorption of nutrients through BBM.