[Changes in the plasma and erythrocyte concentrations of rubidium in patients with renal failure]

Rubidium concentrations were measured by flame emission spectrophotometry in whole blood, plasma and red cells from male and female controls and from dialyzed and non-dialyzed patients of both sexes with chronic renal failure. Rubidium concentrations (mumol/l) in male and female controls respectively were: 2.29 +/- 0.29 and 1.96 +/- 0.46 in plasma: 36..79 +/- 5.90 and 30.19 +/- 6.11 in whole blood; 74.57 +/- 10.37 and 72.22 +/- 12.76 in erythrocytes. The red cell rubidium/plasma rubidium ratios were 32.6 in males and 38.3 in females. Compared with controls, dialyzed male and female patients showed, before dialysis, a decrease in rubidium concentrations of respectively -30% and -17% in plasma, -64% and -61% in whole blood, -40% and -33% in erythrocytes. A further decrease of 25% in rubidium plasma concentrations was observed after dialysis. Non dialyzed patients had an increase in plasma concentrations (+14% in males, +23% in females) and a decrease in erythrocyte concentrations (-16% in males, -20% in females) as compared with controls. Our data show that plasma and red cell rubidium concentrations are fairly constant and probably regulated in healthy subjects but vary considerably in patients with renal failure.