Plasma cholesterol levels in cholesterol-fed rabbits were markedly reduced by the intravenous infusion or bolus injection of recombinant human apo E or rabbit plasma apo E. Administration of 6-70 mg of apo E resulted in an approximately 20-40% acute reduction in plasma cholesterol levels within 2-3 h. Plasma cholesterol levels remained reduced for 4-8 h after the administration of apo E. Furthermore, the intravenous injection of apo E reduced the plasma cholesterol levels in Watanabe heritable hyperlipidemic rabbits. The addition of apo E to [14C]cholesterol-labeled canine thoracic duct lymph or [14C]cholesterol-labeled chylomicrons resulted in accelerated plasma clearance of these diet-induced lipoproteins in normal rabbits, with the uptake occurring primarily in the liver. This study suggests that the amount or availability of apo E in the plasma of cholesterol-fed rabbits may be rate limiting for the normal clearance of diet-induced remnant lipoproteins.


R W Mahley, K H Weisgraber, M M Hussain, B Greenman, M Fisher, T Vogel, M Gorecki


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