Kinetics of taurocholate uptake by isolated ileal cells of guinea pig.
Carrier-mediated uptake of taurocholate by ileal cells of guinea pig had an activation energy of 66 kJ/mol. There was no distinct pH optimum in the physiological pH range. Uptake was efficiently inhibited by cholate and taurochenodeoxycholate in a competitive manner, but less inhibited by bromosulfophthalein and not inhibited by taurine. The rate of uptake was related to the extracellular Na+ concentration up to 90 mM Na+. Stimulation by Na+ (up to sevenfold) occurred only in the presence of a transmembrane Na+ gradient, whereas high extracellular (Na+) in the absence of gradient did not stimulate. It is suggested that taurocholate is bound to a steroid-binding site of the carrier. The energy for the intracellular accumulation is largely provided by cotransport with Na+.
D000818:Animals; D002478:Cells, Cultured; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D007082:Ileum / Q000378:metabolism*; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D007700:Kinetics; D008297:Male; D012964:Sodium / Q000502:physiology; D013656:Taurocholic Acid / Q000378:metabolism*; D013696:Temperature
D013656:Taurocholic Acid; D012964:Sodium