Linked Life Data

1797946

Source:http://linkedlifedata.com/resource/pubmed/id/1797946

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1992-4-15
pubmed:abstractText
Treatment of HepG2 cells in lipoprotein-deficient media with 4,4,10 beta-trimethyl-trans-decal-3 beta-ol (TMD) abolished the incorporation of [3H]acetate into cholesterol with concomitant accumulation of squalene 2,3(S)-oxide and squalene 2,3(S):22(S),23-dioxide, indicating a specific inhibition of oxidosqualene cyclase. The activity of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase was affected in a biphasic manner, being inhibited by 30% at low concentrations of TMD and stimulated by 30% at concentrations that completely shut down oxidosqualene cyclase. Treatment with TMD (greater than 20 micrograms/ml) doubled the specific binding and internalization of low density lipoproteins (LDL) and also enhanced their degradation to a degree comparable to that produced by lovastatin, a well-known inhibitor of HMG-CoA reductase. The enhanced binding of LDL to HepG2 cells appeared to occur as a result of an increase in the number of binding sites with no change in their binding affinity for the lipoprotein. At concentrations that completely inhibited cholesterol biosynthesis, TMD did not affect the ability of LDL-derived cholesterol to stimulate cholesterol esterification by seven- to tenfold or to stimulate bile acid secretion to a lesser degree. However, TMD treatment inhibited overall bile acid secretion by 75-85%. The compound had no inhibitory effect on the rates of secretion of either apolipoprotein B or of cholesterol by HepG2 cells into the culture medium. These data demonstrate that a specific inhibition of the sterol branch of isoprenoid biosynthetic pathway in hepatic cells by TMD is sufficient to induce the expression of LDL receptors and that the cholesterol delivered by LDL is available for normal metabolic purposes of the cell.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-2275
pubmed:author
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1657-65
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Effects of specific inhibition of sterol biosynthesis on the uptake and utilization of low density lipoprotein cholesterol by HepG2 cells.
pubmed:affiliation
Eleanor Roosevelt Institute, Denver, CO 80206.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't