Low-density lipoprotein catabolism in WHHL rabbits after partial ileal bypass surgery.
The effect of partial ileal bypass surgery (PIB) on lipoprotein concentrations and compositions and on the catabolism of low-density lipoproteins (LDL) was studied in Watanabe heritable hyperlipidemic (WHHL) rabbits. After PIB, total serum cholesterol was 65% lower (6.22 +/- 1.58 vs. 17.24 +/- 3.22 mmol/l) and LDL cholesterol 81% lower (2.02 +/- 0.95 vs. 10.90 +/- 3.60 mmol/l) than in control WHHL rabbits; cholesteryl esters, expressed as percentage of mass, were 55% lower in the very-low and intermediate-density lipoprotein (VLDL + IDL) fractions, and 45% lower in LDL, whereas triacylglycerols were 89% higher in VLDL + IDL and 121% higher in LDL. The fractional catabolic rate (FCR) of LDL protein (apoLDL) from operated animals was 10% higher than that from controls in all animals (0.55 +/- 0.10 vs. 0.50 +/- 0.10 pools/day; P less than 0.01). The FCR of autologous apoLDL in PIB rabbits was 50% higher than that of autologous apoLDL in control rabbits (0.63 +/- 0.05 vs. 0.42 +/- 0.06 pools/day); this was not caused by induction of receptor-mediated clearance of LDL. The production rate of apoLDL after PIB in PIB rabbits was 50% lower compared to control apoLDL in controls (26.0 +/- 6.7 vs. 51.7 +/- 16.4 mg/kg per day). We conclude that PIB lowers LDL cholesterol in WHHL rabbits by a decreased production of LDL, by an increased non-specific clearance of LDL and by compositional changes, which lead to LDL particles containing less cholesterol.
Mol
M J
MJ
Department of Medicine, University Hospital Nijmegen, The Netherlands.
Stalenhoef
A F
AF
Demacker
P N
PN
van't Laar
A
A
D000818:Animals; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D015243:Cholesterol, VLDL / Q000097:blood; D004195:Disease Models, Animal; D006938:Hyperlipoproteinemia Type II / Q000097:blood* / Q000601:surgery; D007082:Ileum / Q000601:surgery*; D008074:Lipoproteins / Q000097:blood; D011817:Rabbits
D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D008074:Lipoproteins; C030104:lipoprotein cholesterol; D002784:Cholesterol