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Further characterization of 3'-isothiocyanatobenzamido[3H]cholate binding to hepatocytes. Correlation with bile acid transport inhibition and protection by substrates and inhibitors.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 1985 Sep 25; Vol. 819 (1), pp. 37-44. - Publication Year :
- 1985
-
Abstract
- Binding of 3'-isothiocyanatobenzamido[3H]cholate ([3H]IBCA) to hepatocytes correlates to its efficacy in inhibiting cholate uptake in isolated hepatocytes. The correlation is linear up to 20 microM [3H]IBCA. Labeling of polypeptides is proportional to the degree of inhibition particularly for a protein of molecular weight 50 000. Transported substrates, competitive and non-competitive inhibitors of cholate transport protect against IBCA inhibition. Additionally binding of [3H]IBCA to isolated plasma membranes is prevented by the same substrates and inhibitors of the cholate transport system. The prevention is achieved by taurocholate, iopodate, iodipamide, furosemide, BSP, cyclosporin A, and somatostatin analogs. Protection is correlated to the degree of transport inhibition and depends on the hydrophobicity of the compounds. Other inhibitors known to destroy the driving forces such as valinomycin do not protect membrane proteins against coupling with IBCA. Silybin, which preferentially alters membrane fluidity, has little effect on the labeling. The above results give further evidence that IBCA, when applied in concentrations below 20 microM, is a suitable label for the hepatocellular bile salt transporter.
- Subjects :
- Affinity Labels
Animals
Binding, Competitive
Biological Transport, Active drug effects
Cell Membrane metabolism
Cells, Cultured
Cytosol metabolism
Membrane Fluidity drug effects
Membrane Proteins metabolism
Molecular Weight
Rats
Silymarin pharmacology
Bile Acids and Salts metabolism
Cholic Acids metabolism
Isothiocyanates
Liver metabolism
Thiocyanates metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 819
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 3840036
- Full Text :
- https://doi.org/10.1016/0005-2736(85)90193-2