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- Title
Effects of acute and chronic uremia on active cation transport in rat myocardium.
- Authors
Druml, Wilfred; Kelly, Ralph A.; England, Brian K.; O'Hara, Donald S.; Mitch, William E.
- Abstract
As abnormalities of active cation transport could contribute to the genesis of uremic cardiomyopathy, we investigated myocardial sodium pump function in rats with acute renal failure (ARF) and with a model of experimental chronic renal failure (CRF) that has metabolic similarities to advanced chronic uremia in humans. CRF rats were hypertensive and had left ventricular hypertrophy (33% higher heart: body weight ratio: P < 0.01) at four weeks compared lo pair-fed sham-operated rats. Importantly, both ouabain- and furosemide-sensitive 86Rb uptake rates were unchanged in left ventricular myocardial slices from CRF, and the intracellular sodium concentration was not different from that of control rats even though skeletal muscle sodium was increased, as we found previously (J Clin Invest 81:1197, 1988). Insulin-stimulated, ouabain-sensitive 86Rb influx was also preserved. There also were no abnormalities in myocardium cation transport in rats with ARF. However, [³H]ouabain binding was decreased 45% in CRF rats (P < 0.01); it was unchanged in acute uremia. Decreased ouahain binding in chronic uremia was due entirely to fewer low affinity [³H]ouabain binding sites (the binding affinity for ouabain was unaffected). We conclude that in chronic, (but not acute) renal failure, sodium pump number is reduced in myocardium but intracellular sodium is unchanged and active cation flux rates are maintained. These results emphasize that in rats with chronic uremia, intracellular sodium homeostasis is preserved in myocardium, despite the presence of marked abnormalities of active cation transport in skeletal muscle that are characteristic of chronic uremia.
- Subjects
UREMIA; CARDIOMYOPATHIES; ACUTE kidney failure; CHRONIC kidney failure; LEFT heart ventricle; HYPERTROPHY
- Publication
Kidney International, 1990, Vol 38, Issue 6, p1061
- ISSN
0085-2538
- Publication type
Article
- DOI
10.1038/ki.1990.313