Cholesterol modulates organic cation transport activity and lipid fluidity in rat renal brush-border membranes.
The role of cholesterol in organic cation transport was studied in rat renal brush-border membranes. H+ gradient-dependent uptake of the organic cation tetraethylammonium in brush-border membrane vesicles was stimulated by cholesterol enrichment in a dose-dependent manner. The dissipation rate of the H+ gradient, a driving force for organic cation transport in brush-border membranes, was reduced by cholesterol enrichment. Tetraethylammonium uptake in the absence of H+ gradient was also stimulated by cholesterol enrichment. These findings indicate that cholesterol modulates tetraethylammonium uptake by affecting the intrinsic activity of the organic cation transporter and the H+ gradient dissipation rate. Therefore, cholesterol content should be an important determinant for organic cation transport in renal brush-border membranes.
Nabekura
T
T
Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Japan.
Takano
M
M
Inui
K
K
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002412:Cations; D002784:Cholesterol / Q000494:pharmacology*; D002788:Cholesterol Esters / Q000494:pharmacology; D007668:Kidney / Q000648:ultrastructure*; D007700:Kinetics; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects*; D008871:Microvilli / Q000187:drug effects / Q000502:physiology*; D011522:Protons; D051381:Rats; D017208:Rats, Wistar; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000378:metabolism; D014475:Uncoupling Agents / Q000494:pharmacology
D002412:Cations; D002788:Cholesterol Esters; D011522:Protons; D013757:Tetraethylammonium Compounds; D014475:Uncoupling Agents; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D019789:Tetraethylammonium; D002784:Cholesterol; C013440:cholesteryl succinate