title: Metabolism of very-low-density lipoprotein and low-density lipoprotein containing apolipoprotein C-III and not other small apolipoproteins.
abstract: OBJECTIVE
  We aimed to clarify the influence of apolipoprotein C-III (apoCIII) on human apolipoprotein B metabolism.
  
  
  RESULTS
  We studied the kinetics of 4 very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) types containing: (1) otherApos-CIII-: none of apoCIII, apoAII, apoCI, apoCII, or apoE; (2) otherApos+CIII-: no apoCIII but at least one of the others; (3) otherApos-CIII+: apoCIII, but not any others; and (4) otherApos+CIII+: apoCIII and at least one other. VLDL and IDL otherApos-CIII+ and otherApos-CIII- had similar rates of lipolytic conversion to smaller particles. However, light LDL otherApos-CIII+ compared with otherApos-CIII- had much faster conversion to dense LDL as did light LDL otherApos+CIII+ compared with otherApos+CIII-. VLDL and IDL otherApos-CIII+ had minimal direct removal from circulation, whereas VLDL and IDL otherApos+CIII-, rich in apoE, showed fast clearance. Lipoproteins in fraction otherApos+CIII+ also rich in apoE had very low clearance.
  
  
  CONCLUSIONS
  The results suggest that apoCIII strongly inhibits hepatic uptake of VLDL and IDL overriding the opposite influence of apoE when both are present. The presence of apoCIII on dense VLDL is not associated with slow conversion to IDL, a lipoprotein lipase-dependent process; but when on light LDL, apoCIII is associated with enhanced conversion to dense LDL, a process involving hepatic lipase.
authors.affiliation: Harvard School of Public Health, Boston, Mass 02115, USA.
authors.forename: Carlos O
authors.initials: CO
authors.lastname: Mendivil
authors.forename: Chunyu
authors.initials: C
authors.lastname: Zheng
authors.forename: Jeremy
authors.initials: J
authors.lastname: Furtado
authors.forename: Julian
authors.initials: J
authors.lastname: Lel
authors.forename: Frank M
authors.initials: FM
authors.lastname: Sacks
mesh_terms: D000328:Adult; D053305:Apolipoprotein C-III / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood; D001057:Apolipoproteins E / Q000097:blood; D004041:Dietary Fats / Q000008:administration & dosage / Q000097:blood; D005260:Female; D006801:Humans; D007700:Kinetics; D008049:Lipase / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D053419:Lipoproteins, IDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood*; D008079:Lipoproteins, VLDL / Q000097:blood*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D014280:Triglycerides / Q000097:blood
chemical_list: D053305:Apolipoprotein C-III; D001055:Apolipoproteins B; D001057:Apolipoproteins E; D004041:Dietary Fats; C504173:LIPC protein, human; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D008049:Lipase; D008071:Lipoprotein Lipase