Renal function and cortical Na-K-ATPase activity, abundance and distribution after ischemia-reperfusion in rats

GABRIELA COUX; TRUMPER, L.; ELIAS, M. M.

Biochimica et Biophysica Acta (Enzimology)

Elsevier

Año: 2002 vol. 1586 p. 71 - 80

0006-3002

The effects of ischaemic injury and reperfusion on renal function, cortical ATP content, alkaline phosphatase activity and(Na‡+K‡)-ATPase activity and abundance in cortical homogenates and isolated basolateral and apical membranes wereexamined. Rats were submitted to 5 or 40 min of right renal artery occlusion and 60 min of reperfusion. Renal function of theischaemic^reperfused kidney was studied by conventional clearance techniques. Our results show that 1 h of reperfusion aftera short period of renal ischaemia (5 min) allows the complete restoration of the biochemical features of cortical cells andfunctional properties of the injured kidney. A longer period of ischaemia, such as 40 min, followed by 1 h of reperfusionshowed functional and biochemical alterations. ATP recovered from 26% after 40 min of ischaemia to 50% of control valuesafter 1 h reperfusion. However, renal function was strongly impaired. Brush border integrity was compromised, as suggestedby AP excretion and actin appearance in urine. Although total cortical (Na‡+K‡)-ATPase activity was not different fromcontrols, its distribution in isolated apical and basolateral membranes was abnormal. Remarkably, we detected an increase inK-subunit protein abundance that may suggest that (Na‡+K‡)-ATPase synthesis is promoted by ischaemia^reperfusion.This increase may play an important role in the pathophysiology of ischaemic acute renal failure.