| Abstract: | ![]()
The effects of dietary potassium on the hemodynamics and plasma norepinephrine (NE) kinetics were studied in 10 patients with borderline hypertension. Potassium supplement (96 mEq daily for 5-7 days) induced a significant (p less than 0.05) fall in blood pressure and a slight decrease in cardiac output. Both urine volume and urinary sodium excretion increased significantly (p less than 0.05) for a first few days following the potassium supplement. The baseline values of the half-time of the rapid NE removal from plasma was significantly delayed in the hypertensive patients (1.05 +/- 0.06 min, p less than 0.05) when compared with those (0.88 +/- 0.04) in normal controls. Potassium supplement induced a significant rise in both plasma NE levels and NE outflow rate (p less than 0.01) in the hypertensive patients, while their half-times were significantly shortened (0.89 +/- 0.07 min, p less than 0.01). The pressor responsiveness to exogenously infused NE tended to diminish during the potassium supplement. These findings indicate that a high potassium intake might accelerate the slowed neuronal NE uptake in the hypertensive patients, while a potassium-induced fall in blood pressure might exert a baroreflex stimulation of NE release. As a net result, an increased NE outflow into the circulation has been confirmed. It is likely that a natriuresis-induced volume contraction might be a predominant factor responsible for the early reduction of blood pressure during the high potassium intake. |
