title: Interrelationship between rat serum very low density and high density lipoproteins.
abstract: An exchange of phospholipids and certain peptides among various classes of rat serum lipoproteins has been demonstrated and its nature has been investigated. [(32)P]-Phospholipid from isolated VLDL, prepared in vivo, was transferred to HDL, and to a much lesser extent to LDL, in vivo and in vitro. This difference between HDL and LDL can be abolished by ultracentrifugation of the serum at d 1.21. Unlabeled VLDL acquired [(32)P]phospholipid from HDL of serum. Phospholipid associated with the alpha-lipoprotein component of VLDL exchanged more readily than that associated with the beta-lipoprotein component of VLDL. Generally, the phospholipid species exchange in proportion to their distribution in the lipoproteins. Radioactivity from (3)H-labeled protein of VLDL was transferred to HDL while HDL (3)H-labeled protein in serum was transferred to VLDL during a 20-min incubation. LDL was not involved in the transfer of protein. Protein associated with the alpha-lipoprotein component of VLDL exchanged more readily than that associated with beta-lipoprotein component. Analysis of tritiated apoproteins of VLDL and HDL by polyacrylamide gel electrophoresis revealed that three of the six peptide bands of apo-VLDL exchanged between VLDL and HDL. The data raise the possibility that intact subunits of the VLDL and HDL are being exchanged.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001059:Apoproteins / Q000097:blood; D002499:Centrifugation, Density Gradient; D002855:Chromatography, Thin Layer; D004589:Electrophoresis, Disc; D007930:Leucine / Q000378:metabolism; D008074:Lipoproteins / Q000096:biosynthesis / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000097:blood / Q000378:metabolism; D008297:Male; D010710:Phosphates / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism; D010759:Phosphorus Isotopes; D051381:Rats; D014316:Tritium
chemical_list: D000596:Amino Acids; D001059:Apoproteins; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D010710:Phosphates; D010743:Phospholipids; D010759:Phosphorus Isotopes; D014316:Tritium; D007930:Leucine