Use of analytic density gradient ultracentrifugation for the study of cholesterol distribution between the lipoprotein fractions of serum

1 ml serum were fractionated by analytical ultracentrifugation in a density gradient in the lipoproteins chylomicron/VLDL, LDL, HDL-2 and HDL-3 and the bottom-fraction. The sudan black prestained lipoprotein fractions were separated under visual control. The cholesterol content in the different lipoproteins was determined with the methods according AB (D.L.) and with the cholesterol oxidase/catalase-method. Both methods gives good reproducible and highly correlated results. With the AB (D.L.) method about 97% of the serum cholesterol concentration can be found in the lipoprotein fractions whereas with the enzymatic method about 87% can be detected. By a correlation coefficient of r = 0.989 the AB (D.L.) method gives about 0.30 mmol/l higher cholesterol values compared with the cholesterol oxidase catalase-method. The analytical ultracentrifugation can be recommended for the investigation of the cholesterol distribution between the lipoproteins also in clinical and smaller epidemiological studies.