Uptake of cholic acid by freshly isolated rat hepatocytes: presence of a common carrier for bile acid transports.
The mechanism of the uptake of cholic acids and the interaction of various bile acids on the cholic acid uptake were investigated using isolated rat hepatocytes. The uptake consisted of unsaturable and saturable processes at 0 degrees C and 37 degrees C, respectively. The activation energy found for the saturable process was 26.1 Kcal/mol. In the saturable process the rate of cholic acid uptake followed Michaelis-Menten kinetics with Km: 67 microM and Vmax: 1.43 nmoles/ml protein/min. The uptake was significantly inhibited by 2,4-dinitrophenol, and replacement of extracellular Na+ by choline did not decrease the uptake. The uptake of cholic acid was competitively inhibited by deoxycholic acid, taurocholic acid, glycocholic acid, chenodeoxycholic acid, taurochenodeoxycholic acid and glycochenodeoxycholic acid. It is concluded from the above results that the cholic acid uptake in isolated hepatocytes is mainly mediated by an energy-dependent and sodium-independent carrier-mediated transport process.
D019297:2,4-Dinitrophenol; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002793:Cholic Acids / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
D002793:Cholic Acids; D004140:Dinitrophenols; D007461:Iodoacetates; D010042:Ouabain; D012964:Sodium; D019297:2,4-Dinitrophenol; D019807:Iodoacetic Acid