Phospholipid Studies of Different Serum Lipoproteins Employing P32

Abstract

Administration of P32 to humans by mouth results in labelling of the alpha1, alpha2 and beta lipoproteins separated by zone electrophoresis in a starch supporting medium. Both phospholipid phosphorus and radioactivity of alpha2 lipoprotein fraction increased after ordinary meals. Specific activities of the different lipoproteins were very similar even at various time intervals following the oral radioactive phosphate. The only exception was a slightly higher specific activity for the alpha1 lipoprotein in certain sera taken at early times. In vitro experiments demonstrated transfer of phospholipid radioactivity from labeled beta lipoproteins to unlabeled alpha1 lipoproteins; also from labeled alpha1 lipoproteins to unlabeled beta lipoproteins.