title: The fate of cholesteryl linoleyl ether and cholesteryl linoleate in the intact rat after injection of biologically labeled human low density lipoprotein.
abstract: In vitro labeling of low density lipoproteins (LDL) with [7 alpha(n)-3H]cholesteryl linoleyl ether, and with [4-14C]cholesteryl linoleate was achieved by a modification of the method developed for labeling of very low density lipoproteins. [3H]Cholesteryl linoleyl ether and [14C]cholesteryl linoleate were cosonicated with partially delipidated high density lipoprotein (HDL) and the HDL was purified by centrifugation at d = 1.063. LDL was labeled by incubation of the labeled HDL in the presence of the d greater than 1.25 fraction of human plasma and reisolated at d = 1.063. The 3H/14C ratio in the labeled LDL was the same as in the HDL. The labeled LDL had the same lipid composition and ultrastructural appearance as the non-incubated LDL. After injection into rats, both labels disappeared at similar rates and the t1/2 between 1-24 h was 7.0 h. Up to 8 h after injection of labeled LDL, 94-97% of 3H and 14C radioactivity in the plasma was precipitable by heparin-manganese. 24 h after injection, 28% of the [3H]cholesteryl linoleyl ether was recovered in the liver, 6% in small intestine and 34% in the carcass, and the rest was distributed among all other organs; total recovery of 3H label was 89 +/- 3.0%. The present findings indicate that as in the rat there is no transfer of esterified cholesterol among plasma lipoproteins, LDL is catabolized by both the liver and extrahepatic tissues.
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D014018:Tissue Distribution
chemical_list: D002788:Cholesterol Esters; D008077:Lipoproteins, LDL; C021976:cholesteryl linoleate; C027575:cholesteryl linoleyl ether; D002784:Cholesterol