Original Papers: PDF OnlyIntracellular Electrolytes During Antihypertensive Treatment with a Loop DiureticZidek, Walter; Losse, Heinz; Schmidt, Werner; Fehske, Klaus J.; Vetter, Hans Author Information From the Medizinische Universitats-Poliklinik, Albert-Schweitzer-Strasse 33, D-4400 Münster, West Germany. Requests for reprints to: Prof. Dr H. Vetter, Medizinische Universitats-Poliklink, Albert-Schweitzer-Strasse 33, D-4400 Münster, West Germany Date of receipt: 13 February 1984; revised: 25 May 1984. Journal of Hypertension 2(4):p 393-395, August 1984. Buy Abstract The effect of the loop diuretic, piretanide (12 mg/day on blood pressure and intracellular electrolyte composition in red blood cells during a six-week treatment period was studied in 14 previously untreated essential hypertensive patients. Blood pressure fell continuously during the six weeks, intracellular Na+ activity in red blood cells increased slightly (P < 0.05), and there was a marked decrease in intracellular Ca2+ activity (P < 0.01). Intracellular K+ concentration was not altered. It is concluded therefore, that intracellular free Na+ does not correlate with the actual blood pressure, whereas the fall in blood pressure is associated with a decrease in intracellular free Ca2+, suggesting that intracellular free Ca2+ is involved in the regulation of vascular tone. Journal of Hypertension 2:393-395, 1984 © Lippincott-Raven Publishers.