Incorporation of SE75 Selenomethionine into a Protein Component of Plasma Very-Low-Density Lipoprotein in Man

Abstract

This investigation is designed to examine the intravascular kinetic behavior of apoprotein associated with the very-low-density lipoproteins (VLDL) in man. The incorporation of intravenously injected selenomethionine Se-75 into plasma proteins was examined in ten subjects. A component of the apoprotein associated with the VLDL was isolated by solvent extraction, and was found to have a uniquely short intravascular half-life of one hour, resulting in a plasma flux of 281 mg./day with only 15.3 mg. circulating in the plasma. In patients with abnormal lipemia, this protein was found to have a prolonged intravascular half-life, and an increased intravascular flux of 979 mg./day. This threefold rise in flux was accompanied by an anticipated increased plasma concentration of the isolated protein to levels ranging from 25 to 750 μg./ml., representing a marked rise from the normal plasma concentrations of 4.8 ± 2.9 μg./ml. The data are interpreted as demonstrating a distinct abnormality in the kinetic behavior of Se-75-labeled protein isolated from VLDL from patients with endogenous lipemia.