[Spin label study of plasma lipoproteins].

Lipoprotein structure was studied by means of EPR-spectroscopy of spin probes--iminoxyl derivatives of stearic acid and of androstane--in blood plasma of 40-59 years old men. The mode of wrapping of external monolayer of lipoprotein particles, the type of their intermolecular interactions were similar to corresponding characteristics of bilayer in biological and model membranes. Correlation was observed between concentration of separate lipoproteins in blood plasma and the structural parameters of the probe distribution in hydrophobic and polar regions of the lipoprotein preparations. The phenomena observed might be related to capacity of the high density lipoproteins to accept cholesterol from cell membranes with transfer of cholesterol into liver tissue, where it is subsequently metabolized, as well as to the property of the very low density lipoproteins to transfer cholesterol into tissues, particularly, into vascular walls.