Linked Life Data

8345791

Source:http://linkedlifedata.com/resource/pubmed/id/8345791

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1993-9-3
pubmed:abstractText
Abnormalities of lipid composition and metabolism are frequently observed in patients with cholestatic liver disease. Both elevated low-density lipoprotein (LDL) levels and the appearance of lipoprotein-X (LP-X) in plasma underlie the high incidence of hypercholesterolemia in this population. We tested the hypothesis that the hypercholesterolemia of cholestasis may reflect a failure of normal feedback regulation of hepatic cholesterogenesis by determining the influence of LP-X on the rate-limiting enzyme of cholesterol synthesis, hydroxymethylglutaryl coenzyme A (HMG CoA) reductase. Cultured human hepatoma (HepG2) cells were incubated in purified lipoprotein for 24 hours, harvested, and then assayed for HMG CoA reductase activity and mass. LDL isolated from either normal controls or patients with cholestasis decreased reductase activity in a dose-dependent fashion (2 to 30 micrograms cholesterol/mL media) to a level approximately 50% of that measured in cells incubated in lipid-deficient serum. LP-X failed to downregulate enzyme activity compared with LDL, with little change in reductase activity at cholesterol concentrations (30 micrograms/mL media) that produced maximal reductase inhibition by LDL. Three distinct LP-X subspecies were purified from the plasma of a patient with primary biliary cirrhosis (PBC) and tested in an analogous manner. All LP-X subspecies were similar in their inability to decrease reductase activity as compared with LDL. HMG CoA reductase mass was increased approximately twofold in cells incubated with LP-X, as estimated by Western blot analysis. These results suggest that LP-X may contribute to hypercholesterolemia in the cholestatic patient by not effectively downregulating hepatic cholesterol synthesis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0026-0495
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
807-13
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Lipoprotein-X fails to inhibit hydroxymethylglutaryl coenzyme A reductase in HepG2 cells.
pubmed:affiliation
Department of Medicine (Division of Endocrinology and Metabolism), University of Florida College of Medicine, Gainesville 32610-0226.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't