Serum lipoproteins of normal and cholesterol-fed rats

Abstract

The density distribution of lipoproteins in rats fed chow or chow containing 1% cholesterol and 10% olive oil was studied. Lipoprotein fractions were prepared in the ultracentrifuge between narrow density bands within the density range of 1.006–1.21 and were analyzed by chemical, electrophoretic, and immunological methods. In serum from normal rats there were three major lipoprotein fractions, with densities less than 1.006, 1.030–1.063, and 1.063–1.21. Almost no lipoprotein was found between d 1.006 and 1.030. Most of the low density lipoprotein appeared between a density of 1.04 and 1.05. In the density range 1.05–1.07, small amounts of both low density and high density lipoprotein were found.Feeding a diet high in cholesterol resulted in a marked increase in the concentration of lipoproteins of density less than 1.006, and a new lipoprotein fraction appeared between d 1.006 and 1.030; this fraction contained immunologically demonstrable low density and high density lipoproteins. In addition, there was a decrease in the high density lipoprotein fraction between d 1.070 and 1.21.

Keywords

• quantitative immunoelectrophoresis
• preparative ultracentrifugation
• paper electrophoresis
• atherogenic diet