Increased Plasma Aldosterone Concentration In Response to Hemodialysis In Nephrectomized Man

Abstract

The nephrectomized patient maintained on intermittent hemodialysis while awaiting renal transplantation provides an excellent model for studying the influence of factors other than the renal renin-angiotensin system that play a role in the regulation of plasma aldosterone concentration. Peripheral plasma aldosterone concentrations were determined using a sensitive radioimmunoassay method in nine anephric patients in the recumbent position immediately before and after hemodialysis. Average patient weight fell 1.5 kg following 12 hours of dialysis on the Kiil dialyzer. Plasma sodium concentration decreased from 137 ± 1 (SE) to 132 ± 1 mEq/liter, plasma potassium concentration decreased from 4.8 ± 0.3 to 3.2 ± 0.1 mEq/liter, and the ratio of sodium to potassium increased from 31.3 ± 1.9 to 41.7 ± 0.9. Plasma aldosterone concentration increased from 9.7 ± 1.6 ng/100 ml plasma before dialysis to 17.9 ± 2.1 ng/100 ml plasma after dialysis despite the lack of kidneys to produce renin. Plasma cortisol concentration did not change significantly (17.5 ± 2.0 µg/100 ml plasma to 14.8 ± 1.9 µg/100 ml plasma). These results show that plasma aldosterone concentration increased in anephric patients in response to hemodialysis. This increase occurred without a concomitant increase in plasma cortisol levels, suggesting absence of an adrenocorticotropic hormone response, and was independent of the renal reninangiotensin system.