Relationship between plasma and cellular potassium content during potassium repletion.

The simultaneous effect of two weeks of potassium repletion therapy on the plasma concentration and total body content of potassium was assessed in seven patients with hypokalaemia. Glomerular filtration rate, renal plasma flow, and maximal urinary concentration were also measured both before and after therapy with potassium chloride. While the plasma potassium concentration quickly returned to normal, total body content of potassium remained depressed, emphasizing the unreliability of the plasma potassium concentration as an indicator of total body potassium status. Parameters of renal function measured in this study, which were depressed by potassium depletion, also did not alter with correction of the plasma potassium level. This suggests that these functions are primarily affected by cellular potassium content.