COMPARISON OF EXTRA RENAL POTASSIUM DISPO SAL IN HYPERTENSIVE, DIABETIC AND NORMAL SUBJECTS

Background: Sodium and potassium ions are involved in the regulation o f blood pressure and the genesis of hypertension. Aim: To assess inter nal potassium balance, as a measure of sodium pump activity, in subjec ts with essential hypertension and diabetic patients. Patients and Met hods: Eleven hypertensive subjects, 5 non-insulin-dependent diabetics and 16 age matched controls were studied. An acute oral load of 0.8 mE q/Kg body weight of KCl was administered and blood samples were drawn every 30 min thereafter, until 120 min, to measure plasma K+ levels. U rinary K+ excretion during the period was also measured. In eight hype rtensive patients, the test was repeated after two week of supplementa tion with 60 mEq/day of KCl. The maximal increase in plasma potassium levels and the time required to achieve the maximum concentration was recorded. Results: All patients had normal serum creatinine levels. Me an fasting blood glucose of diabetic patients was 133 +/- 15.1 mg/dl. No difference between patients and controls in maximal increase plasma potassium increase, was observed. In hypertensive patients the lapse to achieve the maximal potassium concentration was longer than in cont rols. After the period of potassium supplementation in hypertensive pa tients, there was a significant increase in basal plasma K+ levels and the temporal pattern of plasma potassium increase was similar to that of controls. Between 63 and 68% of retained K+ load was translocated to the intracellular space at 120 min in all study groups. Conclusions : Internal potassium balance is not significantly altered in subjects with essential hypertension or in non-insulin-dependent diabetics.