Sodium transport parameters in erythrocytes of patients with primary aldosteronism

J B Smith, M B Wade, N S Fineberg, M H Weinberger
1988 Hypertension  
Primary aldosteronism is an uncommon cause of hypertension but one of particular interest because of its distinctive pathophysiological mechanism of blood pressure elevation. Aldosterone has been associated with increased Na + ,K+-adenosine triphosphatase (ATPase) activity, but there is controversy over which sodium transport parameters are responsible for this increase. We measured intracellular sodium, ouabain-sensitive and ouabain-insensitive sodium efflux, and the number of Na + ,K +
more » ... sites of washed erythrocytes, as well as Na+-Li + countertransport and the L1+-K+ cotransport rate constant of lithium-loaded red blood cells (RBCs) in six patients with primary aldosteronism and in 50 normal subjects. Ouabain-sensitive sodium efflux was significantly (p< 0.001) higher for the primary aldosteronism patients than for normal subjects (1.85 ± 0.29 vs 1.51 ± 0.21 mmol/L RBC/hr) even though the intracellular sodium concentration (7.2 ± 1.5 vs 6.7 ± 1.9 mM) and the number of the Na+,K+-ATPase sites per RBC (331 ± 52 vs 385 ± 97) were not increased. The elevated sodium efflux appeared to be due to a significant (p<0.001) increase in the rate constant (1.60 ± 0.12 x 10-" vs 1.28 ± 0.15 x 10-" mmol/site/hr) of the ouabain-sensitive sodium efflux. The rate constant decreased significantly (p<0.01) after treatment.
doi:10.1161/01.hyp.11.2.141 pmid:2449394 fatcat:d5ftd4ets5ggjmlnarjzxnqohy