[Redistribution of rabbit blood serum lipoproteins, caused by a one-time administration of cholesterol].

The redistribution of rabbit blood serum lipoproteins following 24-hr incubation of the sera at 37 degrees C and after a single injection of cholesterol (0.2 g/kg) was studied. In both cases there was an increase in the intermediate density (IDL) and low density lipoproteins (LDL) and a sharp decrease in very low density lipoproteins (VLDL). The proportion of the total fraction of high density lipoproteins (HDL) decreased also. The redistribution of the HDL subpopulations against the background of the HDL decline after a single cholesterol dose seems to be due to a relative increase in HDL3 and a decrease in HDL2. The HDL transformation during heat incubation of control sera was accompanied by HDL3 conversion into HDL2. These data suggest that a single cholesterol dose and heat incubation of blood sera stimulate the direct and reverse cholesterol transport. In isolated sera these processes subside gradually. The inhibition mechanism entails the depletion of the lipoprotein system for chylomicrons and VLDL and exhaustion of HDL2. The restoration of the functional potential of the blood lipid-transporting system needs the exchange between lipoproteins and tissues.