Cholesterol exchange between human serum isolated lipoproteins. Effect of protein concentration.

The in vitro transfer of radiolabelled unesterified cholesterol from human low- and very low- to high-density lipoproteins in the presence of either lipoprotein deficient serum or bovine serum albumin has been studied. The rate of transfer was faster from LDL (t1/2 = 44 min) than from VLDL (55 min). The presence of 2% protein had no effect on the transfer. However, 10% albumin or lipoprotein deficient serum reduced t1/2 by 35%, which indicates no specific effect of a plasma protein on the rate of transfer of unesterified cholesterol.