Relation of Cellular Potassium to Other Mineral Ions in Hypertension and Diabetes

To investigate the role of intracellular potassium (Ki)and other ions in hypertension and diabetes, we utilized K-, Na-, P-, and F-nuclear magnetic resonance (NMR) spectroscopy to measure Ki, intracellular sodium (Nai), intracellular free magnesium (Mgi), and cytosolic free calcium (Cai), respectively, in red blood cells of fasting normotensive nondiabetic control subjects (n=10), untreated (n=13) and treated (n=14) essential hypertensive subjects, and diabetic subjects (n=5). In 12 subjects (6 hypertensive and 6 normotensive controls), ions were also measured before and after the acute infusion of 1 L of normal saline. Compared with those in controls (Ki=148±2.0 mmol/L), Ki levels were significantly lower in hypertensive (132.2±2.9 mmol/L, sig=0.05) and in type 2 diabetic subjects (121.2±6.8 mmol/L, sig=0.05). Ki was higher in treated hypertensives than in untreated hypertensives (139±3.1 mmol/L, sig=0.05) but was still lower than in normals. Although no significant relation was observed between basal Ki and Nai values, saline infusion elevated Nai (P