Potassium load in spontaneously hypertensive rats. Effects on blood pressure, renin-angiotensin, aldosterone, and intracellular electrolytes.
To study the mechanisms by which K+ influences vascular tone in hypertension, spontaneously hypertensive and normotensive rats were examined during an oral K+ load. There was a marked decrease in blood pressure in spontaneously hypertensive but not in normotensive rats. Intraerythrocytic K+ concentration and activity increased in normotensive but not in spontaneously hypertensive rats. Intraerythrocytic Na+ concentration and activity declined in both strains, the decrease in Na+ activity being more prominent in spontaneously hypertensive rats (P less than 0.05). Intraerythrocytic Ca2+ activity decreased in spontaneously hypertensive rats (P less than 0.01) but not in normotensive rats. In both strains plasma aldosterone concentration increased during K+ load, the plasma renin activity being suppressed. The basal levels of plasma aldosterone in spontaneously hypertensive rats exceeded those in normotensive rats. It is concluded that intraerythrocytic Ca2+, and to a lesser extent Na+, correlate best with the blood pressure changes. These ionic changes may be mediated by hormonal factors. The significance of the elevated plasma aldosterone levels has not yet been entirely clarified.
D000450:Aldosterone / Q000097:blood*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D004573:Electrolytes / Q000378:metabolism*; D006973:Hypertension / Q000503:physiopathology*; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011922:Rats, Mutant Strains; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012964:Sodium / Q000378:metabolism
D004573:Electrolytes; D000450:Aldosterone; D012964:Sodium; D011188:Potassium; D002118:Calcium