Altered potassium homeostasis in Crohn's disease.

The total body potassium (TBK), serum potassium, and the number of red blood cell ouabain-binding sites was studied in 94 patients with Crohn's disease. TBK was measured by counting the endogenous 40K in a whole body counter. TBK was 87% +/- 13% in 94 patients with Crohn's disease, while in control subjects, it was 97% +/- 12% (n = 24). This significant reduction in TBK was accompanied by normal serum potassium levels (4.4 +/- 0.5 mM). TBK was significantly correlated with the Crohn's disease activity index (r = 0.79, n = 113, P less than 0.01). The number of red cell ouabain binding sites measured by equilibrium binding of 3H-ouabain showed a significant increase in the number of Na-K pumps in Crohn's disease (396 +/- 65, n = 27) compared with the control group (290 +/- 45; n = 24). These results support the suggestion that changes in TBK may regulate the synthesis of Na-K pump molecules. The total body potassium depletion and the need for a preoperative nutritional support in Crohn's disease are discussed.