Relation of plasma renin to end organ damage and to protection of K+ feeding in stroke-prone hypertensive rats

Massimo Volpe, Maria J F Camargo, Franco B. Mueller, Wallace G. Campbell, Jean E. Sealey, Mark S. Pecker, R. Ernest Sosa, John H. Laragh, Antoinette Rookard

Research output: Contribution to journalArticlepeer-review

Abstract

We studied the effects of regular diet (035% NaCl/1.1% potassium), high sodium diet (4% NaCl/0.75% potassium), or high sodium and high potassium diet (4% NaCl/2.11% potassium) on blood pressure, plasma renin activity, renal and cerebrovascular lesions, and incidence of stroke and mortality in male stroke-prone spontaneously hypertensive rats (SHRSP). In the first 4 weeks, the rise in blood pressure was higher in high NaCl than in high NaCl/high potassium or regular diet groups. However, by 8 and 12 weeks, the blood pressure in all three groups was similar. After 4 weeks of diet, plasma renin activity was similar in the three groups (3.4±0.8, 4.1±0.9, and 5.2±1.6 ng/ml/hr, in high NaCl, high NaCl/high potassium, and regular diet groups, respectively) and were not related to sodium excretion. After 8 weeks, plasma renin activity was significantly increased only in the high NaCl group (13.7±3.7 ng/ml/hr), and by 12 weeks plasma renin activity was significantly higher in the high NaCl group (25.3±3.6 ng/ml/hr) than in the high NaCl/high potassium (11.1±2.9 ng/ml/hr) or in the regular diet (7.8±4.6 ng/ml/hr) groups. Moderate to severe renal vascular lesions were first detected in the high NaCl group by 8 weeks of diet. At 12 weeks, renal vascular damage index (RVDI), estimated histologically, was significantly higher in the high NaCl group (RVDI=79±14) than in the high NaCl/high potassium (RVDI=40±11) and regular diet (RVDI=7.8±4.6) groups. At this time, incidence of stroke was 81% in high NaCl, 24.5% in high NaCl/high potassium, and 7.7% in regular diet groups. The data demonstrate that: 1) the increase in mortality, stroke, and renal and cerebrovascular lesions in SHRSP fed a high sodium diet is associated with a paradoxical rise in plasma renin activity; 2) the protective effect of high potassium in SHRSP fed a high potassium diet is related to a lower blood pressure at 2-4 weeks and a lower plasma renin activity, but not a lower blood pressure at 8-12 weeks; 3) this rise in plasma renin activity demonstrates that a high potassium diet suppresses or delays a primary or secondary paradoxical rise in plasma renin activity and thus, angiotensin II in the rats fed a high sodium diet. This action together with possible direct effects of potassium in the vasculature contributes to the protective effect on end organ damage and stroke in SHRSP.

Original languageEnglish
Pages (from-to)318-326
Number of pages9
JournalHypertension
Volume15
Issue number3
Publication statusPublished - Mar 1990

Keywords

  • Aldosterone
  • Angiotensin II
  • Atrial natriuretic factor
  • Blood pressure
  • Malignant hypertension

ASJC Scopus subject areas

  • Internal Medicine

Fingerprint Dive into the research topics of 'Relation of plasma renin to end organ damage and to protection of K+ feeding in stroke-prone hypertensive rats'. Together they form a unique fingerprint.

Cite this