RESUMEN
A new modified procedure is described for preparative production of three subfractions of high density lipoproteins (HDL) by means of salt density gradient developed in ultracentrifugation. Concentrations of cholesterol, phospholipids and apoprotein A-1 in both subfractions HDL2b and HDL2 alpha were found to alter simultaneously with the level of HDL cholesterol in blood plasma of the patients with low, normal and increased content of HDL cholesterol (10 men in each group), thus suggesting the alteration of the particles amount in both these subfractions. In hyperalphacholesterolemia the level of all the components studied was unaltered as compared with normal state, and in hypoalphacholesterolemia only cholesterol containing in HDL3 was decreased due to diminished loading of the particles with cholesterol, as calculated per a unit of apoprotein A-1. The data obtained suggest that alterations in amount of both HDL2b and HDL2a particles depended on intensity of lipid binding, especially of cholesterol, to particles of the HDL3 subfraction, which plays an important role in various physiological and pathological states.