Altered expression of rat renal cortical OAT1 and OAT3 in response to bilateral ureteral obstruction

VILLAR, SILVINA RAQUEL; BRANDONI ANABEL; NAOHIKO ANZAI; HITOSHI ENDOU; TORRES, ADRIANA.

KIDNEY INTERNATIONAL

Nature Publishing Group.

Lugar: United States; Año: 2005 vol. 38 p. 2704 - 2713

0085-2538

Bilateral ureteral obstruction (BUO) is characterized by the development of hemodynamic and tubular lesions. However, little is known about the expression of organic anion renal transporters. The objective of this work was to study the renal excretion of p-aminohippurate (PAH) and the cortical renal expression of the organic anion transporter 1 (OAT1) and organic anion transporter 3 (OAT3) in BUO rats. Methods: Male Wistar rats underwent bilateral obstruction of the proximal ureters for 24 h (BUO) or sham operation (Sham). After 24 h of ureteral releasing, the following studies were performed: PAH renal excretion employing conventional clearance techniques, OAT1 and OAT3 abundance (homogenates, intracellular and basolateral plasma membrane fractions from renal cortex) using immunoblotting and immunocytochemical techniques (light microscopic and confocal immunofluorescence microscopic analysis). BUO rats showed a lower renal excretion of PAH. In obstructed kidneys, immunoblotting revealed a significant decrease in the abundance of both OAT1 and OAT3 in basolateral plasma membranes from renal cortex. An increase of OAT1 expression was observed in homogenates and in intracellular membrane fractions in kidneys from BUO rats compared with Sham ones, indicating an internalization of this carrier. Immunocytochemical techniques confirmed these results. On the contrary, OAT3 expression was reduced both in homogenates and in intracellular membrane fractions in obstructed kidneys. Conclusion: BUO was associated with downregulation of OAT1 and OAT3 in basolateral plasma membranes from proximal tubule cells, thus these carriers may play important roles in the impaired organic anion excretion displayed in the obstructed kidney.