Studies on the Electrolyte Metabolism of Blood Cells (II) : Relationships of Renal Na and K Excretion with Na and K Content in Blood Cells

Abstract

In a previous paper we have reported the increased sodium content of blood cells in edematous state and in patients with severe cardiovascular and renal diseases. The purpose of the present paper is to show the correlations between the sodium and potassium levels of blood cells and the renal excretion of them. Materials and Methods In 74 patients including 21 cases of acute and subacute glomerulonephritis, 1 9 of chronic glomerulonephritis, 3 of nephrotic syndrome, 18 of essential hypertension and nephrosclerosis, and 13 of heart diseases, clearance tests were performed by infusion of PAH and mannitol. Sodium and potassium reabsorption rates were calculated from the values of electrolyte clearance and of glomerular filtration rate. The U/P value, which represents the ratio of total sodium and potassium concentration in urine to that in blood plasma also was calculated. Some authors assume the free water clearance (CH20) as CH20=V-COSM where V is urinary volume and COSM is osmotic clearance, and solute-free water reabsorption (TCH20=Cosm-V From these equations CH20=V(1-Uosm/Posm) TCH20=V(Uosm/Posm-1) can be induced. Then, if Uosm/Posm is greater than unit, the subject should be supposed to be in a state to excrete more solute than water, and vice versa. Following this conception, the value of U/P may indicate whether the subject is in diuretic phase or in saluretic phase. Summary and Conclusion As a whole, sodium clearance was significantly correlated with GFR, but was markedly decreased in the cases whose GFR was below about half of normal value. It also showed smaller value when RPF was markedly decreased and markedly increased than normal. It was diminished in hyponatremic and in hypernatremic subjects, too. No definite correlation between the blood cell sodium level and the amount of sodium excretion was observed. It is accordingly conceivable that sodium clearance which represents the absolute amount of sodium excretion is regulated by body requirement of sodium to maintain the extracullular level within normal range. From the relationship between GFR and sodium reabsorption rate, the amount of sodium excretion were suggested to increase in acute glomerulonephritis and in some cases of essential hypertension. From the value of U/P however, it was also suggested that patients with acute or subacute glomerulonephritis were in more diuretic state than those with chronic ones.