Linked Life Data

2307668

Source:http://linkedlifedata.com/resource/pubmed/id/2307668

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1990-4-9
pubmed:abstractText
Lipoprotein lipase (LPL)-mediated hydrolysis of triglycerides (TG) contained in chylomicrons requires the presence of a cofactor, apolipoprotein (apo) C-II. The physiological mechanism by which chylomicrons gain apoC-II necessary for LPL activation in whole plasma is not known. Using a gum arabic stabilized TG emulsion, activation of LPL by lipoprotein apoC-II was studied. Hydrolysis of TG by LPL was greater in the presence of serum than with addition of either high density lipoproteins (HDL) or very low density lipoproteins (VLDL). LPL activation by either VLDL or HDL increased with addition of the lipoprotein-free fraction of plasma. A similar increase in LPL activity by addition of the lipoprotein-free fraction together with HDL or VLDL was observed when another TG emulsion (Intralipid) or TG-rich lipoproteins from an apoC-II deficient subject were used as a substrate. Human apoA-IV, apoA-I, apoE, and cholesteryl ester transfer protein were assessed for their ability to increase LPL activity in the presence of VLDL. At and below physiological concentrations, only apoA-IV increased LPL activity. One hundred percent of LPL activity measured in the presence of serum was achieved using VLDL plus apoA-IV. In the absence of an apoC-II source, apoA-IV had no effect on LPL activity. Removal of greater than 80% of the apoA-IV from the nonlipoprotein-containing fraction of plasma by incubation with Intralipid markedly reduced its ability to activate LPL in the presence of VLDL or HDL. Gel filtration chromatography demonstrated that incubation of the nonlipoprotein-containing fraction of plasma with HDL and the TG emulsion caused increased transfer of apoC-II to the emulsion and association of apoA-IV with HDL. Our studies demonstrate that apoA-IV increases LPL activation in the presence of lipoproteins. We hypothesize that apoA-IV is required for efficient release of apoC-II from either HDL or VLDL, which then allows for LPL-mediated hydrolysis of TG in nascent chylomicrons.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4266-72
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Lipoprotein ApoC-II activation of lipoprotein lipase. Modulation by apolipoprotein A-IV.
pubmed:affiliation
Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York 10032.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't