title: Beta-very low density lipoproteins in cholesterol-fed rabbits are of hepatic origin.
abstract: When rabbits are fed a cholesterol-rich diet they accumulate beta-migrating very low density lipoprotein (beta-VLDL) in their plasma. beta-VLDL are cholesteryl ester-rich lipoproteins which contain apolipoproteins B and E. There are 2 forms of apolipoprotein B in beta-VLDL. About 90% of apolipoprotein B is present as a 320 000-dalton protein and the remainder is present as a 210 000-dalton protein. These apolipoproteins are tissue specific. Lipoproteins secreted by perfused rabbit livers contain only the 320 000-dalton apolipoprotein B while lipoproteins secreted by the intestine contain only the 210 000-dalton apolipoprotein B. The tissue specificity of apolipoprotein B shows that beta-VLDL is largely of hepatic origin and that only a small fraction is of intestinal origin. The composition of VLDL secreted from the livers of cholesterol-fed rabbits is similar to that of plasma beta-VLDL. Both are cholesteryl ester-rich, in contrast to plasma and perfusate VLDL from normal rabbits which are both triglyceride-rich. This indicates that the cholesteryl ester-rich hepatic VLDL is a direct precursor for plasma beta-VLDL.
mesh_terms: D000818:Animals; D001055:Apolipoproteins B / Q000096:biosynthesis / Q000302:isolation & purification; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D002914:Chylomicrons / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000096:biosynthesis* / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008196:Lymph / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D010477:Perfusion; D011817:Rabbits
chemical_list: D001055:Apolipoproteins B; D002791:Cholesterol, Dietary; D002914:Chylomicrons; D008079:Lipoproteins, VLDL