ABSTRACT
With aging the kidney exhibits progressive deterioration, with a decrease in renal function. Most of the filtered Na+ is actively reabsorbed in the proximal tubules through different transporters located in apical membrane. This process is possible because basolateral Na+/K+-ATP-ase generates electrochemical conditions necessary for energetically favorable Na+ transport. The α-subunit is the catalytic domain of Na+/K+-ATP-ase. There are three isoforms of the α/subunit present in rat kidney. The present study was undertaken to examine the expression pattern of rat α-Na+/K+-ATP-ase during senescence. We tested the impact of aging on mRNA expression of α-Na+/K+-ATP-ase in cortex and medulla of aged Wistar rats. We observed a significant expression decrease in mRNA levels and a possible change of isoform in the cortex of aged animals. These expression changes observed for αsubunit could be contributing to affect the renal function in conditions of water and salt stress.
Con el avance de la edad los riñones exhiben un deterioro funcional progresivo con disminución de la función renal. La mayor parte del sodio (Na+) filtrado es reabsorbido activamente en los túbulos proximales a través de diferentes transportadores ubicados en la membrana apical. Este proceso es posible por la existencia de la Na+/K+-ATP-asa basolateral, que genera las condiciones electroquímicas necesarias para que el transporte de Na+ sea energéticamente favorable. La subunidad αde la Na+/K+-ATP-asa es el dominio catalítico de la enzima. Existen tres isoformas de subunidad α, que están presentes en el riñón de la rata. En este trabajo se examinan los patrones de expresión de la α-Na+/K+-ATP-asa durante la senescencia. Se estudió así si el aumento de la edad incidía en la expresión del ARNm de la α-Na+/K+-ATP-asa en corteza y médula renal de ratas Wistar senescentes. Se observó una disminución en la expresión del ARNm de la subunidad αy un posible cambio de isoforma predominante en la corteza de los animales senescentes. Los cambios observados para la expresión de la subunidad αpodrían contribuir a afectar la función renal en condiciones de estrés hídrico y salino.
Subject(s)
Animals , Rats , Aging/metabolism , RNA, Messenger/metabolism , Sodium-Potassium-Exchanging ATPase/metabolism , Kidney Cortex/enzymology , Kidney Medulla/enzymology , Sodium/metabolism , RNA, Messenger/analysis , Base Sequence , Random Allocation , Rats, Wistar , Sodium-Potassium-Exchanging ATPase/analysis , Sodium-Potassium-Exchanging ATPase/geneticsABSTRACT
Background. The effect of bromoethylamine (BEA) administration on lipid peroxidation and on the activieties of antioxidant enzymes was studied. Methods. Adult rats received BEA at 1.2 mmol/kg, a dose that produces renal papillary necrosis. Lipid peroxidation assessed by maximal rate in MDA formation, the activities of catalase, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the levels of non-protein sulfhydryls (NPSH) were measured in renal cortex and papilla of control and BEA-treated animals. Results. After BEA treatment, an increment in lipid peroxidation in papilla and cortex was found after 1.5 and 24 hours of treatment. Catalase activity decreased in both regions, but earlier cortex. Conclusion. These data suggest some role of oxidative stress in the mechanism of BEAinduced papillary necrosis