NORMAL SENSITIVITY OF NA+/K+-ATPASE ISOLATED FROM BRAIN AND KIDNEY OF SPONTANEOUSLY HYPERTENSIVE RATS TO SODIUM, OUABAIN OR MERCURY

Genetically hypertensive rats are excellent animal models for investigating putative Na+/K+-ATPase alterations associated with the disease. Highly purified Na+/K+-ATPase preparations from these animals have not yet been examined. Na+/K+-ATPase of two strains of spontaneously hypertensive rats, the Milan hypertensive strain (MHS) and the spontaneously hypertensive rat (SHR) were characterized in comparison with enzymes isolated from their matched normotensive controls; the sensitivity to Na ions as well as the shape and span of the inhibition curves for ouabain and mercury of the isolated Na+/K+-ATPases were compared. No functional changes between the purified 'normotensive' and 'hypertensive' Na+/K+-ATPases from brain and kidney were detected ruling out drastic structural alterations of the transport system in these two organs of diseased animals.