Catabolism of very low density lipoproteins in the rabbit. Effect of changing composition and pool size.
To determine the metabolic mechanism of hypercholesterolemia in rabbits produced by feeding cholesterol-rich diets, control and hypercholesterolemic rabbits were injected with I-labelled very low density lipoproteins (VLDL, d 1.006 g/ml) from control and/or hypercholesterolemic donors. Apolipoprotein B in VLDL decayed biphasically. The first phase occurred much more rapid than the second. 95% of the VLDL apolipoprotein B was catabolized via the first phase (t1/2 = 0.55 +/- 0.19 h) in normal rabbit with the immediate appearance of this radioactivity in intermediate density lipoproteins (IDL, d 1.006-1.025 g/ml) and low density lipoproteins (LDL, d 1.025-1.063 g/ml). The apolipoproteins C and E at the same time were transferred to high density lipoproteins where they decayed biphasically. The apolipoprotein B from hypercholesterolemic VLDL in the normal recipient disappeared at a similar rate as from normal VLDL via phase I; however, it was incompletely converted to IDL and LDL. Apolipoprotein B from normal VLDL in cholesterol-fed rabbits disappeared at a normal rate via phase I, but only 82% was catabolized by this phase. Hypercholesterolemic VLDL injected into the hypercholesterolemic recipient was less rapidly catabolized via phase I (T1/2 = 2.5 +/- 0.89 H) and only a small fraction was converted to IDL and LDL.
D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D002791:Cholesterol, Dietary / Q000378:metabolism; D005260:Female; D006937:Hypercholesterolemia / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008079:Lipoproteins, VLDL / Q000097:blood*; D010743:Phospholipids / Q000097:blood; D011817:Rabbits; D014280:Triglycerides / Q000097:blood
D001053:Apolipoproteins; D002791:Cholesterol, Dietary; D008074:Lipoproteins; D008079:Lipoproteins, VLDL; D010743:Phospholipids; D014280:Triglycerides; D002784:Cholesterol