AIM: To examine renal expression of organic anion transporter 5(Oat5) and sodium-dicarboxylate cotransporter 1(Na DC1), and excretion of citrate in rats with acute extrahepatic cholestasis.METHODS: Obstructive jaundice was induced in rats by double ligation and division of the common bile duct(BDL group). Controls underwent sham operation that consisted of exposure, but not ligation, of the common bile duct(Sham group). Studies were performed 21 h after surgery. During this period, animals were maintained in metabolic cages in order to collect urine. The urinary volume was determined by gravimetry. The day of the experiment, blood samples were withdrawn and used to measure total and direct bilirubin as indicative parameters of hepatic function. Serum and urine samples were used for biochemical determinations. Immunoblotting for Oat5 and Na DC1 were performed in renal homogenates and brush border membranes from Sham and BDL rats. Immunohistochemistry studies were performed in kidneys from both experimental groups. Total RNA was extracted from rat renal tissue in order to perform reverse transcription polymerase chain reaction. Another set of experimental animals were used toevaluate medullar renal blood flow(m RBF) using fluorescent microspheres.RESULTS: Total and direct bilirubin levels were significantly higher in BDL animals, attesting to the adequacy of biliary obstruction. An important increase in m RBF was determined in BDL group(Sham: 0.53 ± 0.12 m L/min per 100 g body weight vs BDL: 1.58 ± 0.24 m L/min per 100 g body weight, P < 0.05). An increase in the urinary volume was observed in BDL animals. An important decrease in urinary levels of citrate was seen in BDL group. Besides, a decrease in urinary citrate excretion(Sham: 0.53 ± 0.11 g/g creatinine vs BDL: 0.07 ± 0.02 g/g creatinine, P < 0.05) and an increase in urinary excretion of H+(Sham: 0.082 ± 0.03 μmol/g creatinine vs BDL: 0.21 ± 0.04 μmol/g creatinine, P < 0.05) were observed in BDL animals. We found upregulations of both proteins Oat5 and Na DC1 in brush border membranes where they are functional. Immunohistochemistry technique corroborated these results for both proteins. No modifications were observed in Oat5 m RNA and in Na DC1 m RNA levels in kidney from BDL group as compared with Sham ones.CONCLUSION: Citrate excretion is decreased in BDL rats, at least in part, because of the higher Na DC1 expression. Using the outward gradient of citrate generated by Na DC1, Oat5 can reabsorb/eliminate different organic anions of pathophysiological importance. AIM: To examine renal expression of organic anion transporter 5 (Oat5) and sodium-dicarboxylate cotransporter 1 (Na DC1), and excretion of citrate in rats with acute extrahepatic cholestasis. METHODS: Obstructive jaundice was induced in rats by double ligation and division of the common bile duct (BDL group). Controls underwent sham operation that consisted of exposure, but not ligation, of the common bile duct (Sham group). Studies were performed 21 h after surgery. During this period, animals were maintained in metabolic cages in order to collect urine. The day of the experiment, blood samples were withdrawn and used to measure total and direct bilirubin as indicative parameters of hepatic function. Serum and urine samples were used for biochemical determinations. Immunoblotting for Oat5 and Na DC1 were performed in renal homogenates and brush border membranes from Sham and BDL rats. Immunohistochemistry studies were performed in kidneys fr Total set of experimental animals were used to evaluate the medullar renal blood flow (m RBF) using fluorescent microspheres. RESULTS: Total and direct bilirubin levels were significantly higher in BDL animals, attesting to the adequacy of the biliary obstruction. An important increase in m RBF was determined in the BDL group (Sham: 0.53 ± 0.12 m L / min per 100 g body weight vs BDL: 1.58 ± 0.24 m L / An increase in the urinary volume was observed in BDL animals. An important decrease in urinary levels of citrate was seen in BDL group. Besides, a decrease in urinary citrate excretion (Sham: 0.53 ± 0.11 g / g creatinine vs BDL: 0.07 ± 0.02 g / g creatinine, and an increase in urinary excretion of H + (Sham: 0.082 ± 0.03 μmol / g creatinine vs BDL: 0.21 ± 0.04 μmol / P <0.05) were observed in BDL animals. We founNo modifications were observed in Oat5 m RNA and in Na DC1 m RNA levels in kidney from BDL group as compared with Sham ones. CONCLUSION: Citrate excretion is decreased in BDL rats, at least in part, because of the higher Na DC1 expression. Using the outward gradient of citrate generated by Na DC1, Oat5 can reabsorb / eliminate different organic anions of pathophysiological importance.