Document Detail

Bile salts in submicellar concentrations promote bidirectional cholesterol transfer (exchange) as a function of their hydrophobicity.
MedLine Citation:
PMID:  2373956     Owner:  NLM     Status:  MEDLINE    
Cholesterol, despite its poor solubility in aqueous solutions, exchanges efficiently between membranes. Movement of cholesterol between different subcellular membranes in the hepatocyte is necessary for assembly of lipoproteins, biliary cholesterol secretion, and bile acid synthesis. Factors which initiate and facilitate transfer of cholesterol between different membranes in the hepatocyte are incompletely understood. It is known that cholesterol secretion into the bile is linked to bile salt secretion. In the present study, we investigated the effects of bile salts of different physicochemical properties at submicellar concentrations (150- 600 microM) on the transfer of [14C]cholesterol from hepatocytes, or crude hepatocellular membranes (donors), to rat high density lipoproteins (acceptor). Bile salts included taurine conjugates of ursodeoxycholic acid (TUDCA), hyodeoxycholic acid (THDCA), cholic acid (TCA), chenodeoxycholic acid (TCDCA), and deoxycholic acid (TDCA). High density lipoprotein (HDL) was separated from hepatocellular membranes and the transfer of [14C]cholesterol from the membranes to HDL was quantitatively determined. In the absence of HDL, [14C]cholesterol remained confined to the membrane fraction. Following addition of HDL, [4-14C]cholesterol in the HDL fraction increased linearly over time. Addition of hydrophilic bile salts (TUDCA and THDCA) increased transfer of [4-14C]cholesterol to HDL only minimally. By contrast, more hydrophobic bile salts stimulated transfer of labeled cholesterol to HDL, and their potency increased in order of increasing hydrophobicity (TCA less than TCDCA less than TDCA). Both for single bile salts and mixtures of bile salts at a total bile salt concentration of 0.30 mM, the rate of cholesterol transfer exhibited a strong linear correlation with a bile salt monomeric hydrophobicity index (r = 0.95; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Z R Vlahcevic; E C Gurley; D M Heuman; P B Hylemon
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of lipid research     Volume:  31     ISSN:  0022-2275     ISO Abbreviation:  J. Lipid Res.     Publication Date:  1990 Jun 
Date Detail:
Created Date:  1990-08-27     Completed Date:  1990-08-27     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376606     Medline TA:  J Lipid Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1063-71     Citation Subset:  IM    
Department of Medicine, (Division of Gastroenterology), Medical College of Virginia, Richmond 23298.
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MeSH Terms
Bile Acids and Salts / pharmacology*
Cell Membrane / drug effects,  metabolism
Cells, Cultured
Cholesterol / metabolism*
Cholesterol, HDL / biosynthesis*
Lipoproteins, HDL / metabolism*
Liver / drug effects,  metabolism*
Rats, Inbred Strains
Grant Support
Reg. No./Substance:
0/Bile Acids and Salts; 0/Cholesterol, HDL; 0/Lipoproteins, HDL; 57-88-5/Cholesterol

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