Systemic and regional hemodynamic effects of dietary calcium supplementation in mineralocorticoid hypertension

Donald J. DiPette, Philip E. Greilich, Nancy E. Kerr, Gary A. Graham, O. Bryan Holland

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

This study was undertaken to determine the systemic and regional hemodynamic effects of long-term dietary calcium supplementation in mineralocorticoid (DOC)-salt hypertension. Systemic and regional hemodynamic measurements were determined by the radioactive microsphere technique in conscious and unrestrained rats (kidneys intact) with DOC-salt-induced hypertension that were pair-fed either a normal calcium (0.6% by weight, n=12) or a calcium-supplemented (high-calcium) diet (2.5% by weight, n=12). After 7 to 8 weeks, there were no differences in weight, heart rate, or cardiac output between the two groups. In contrast, the high-calcium rats had a significantly lower mean blood pressure (125±4 mm Hg, mean±SEM) than the normal calcium rats (143±5 mm Hg); this finding appeared to result predominantly from a reduction in total peripheral resistance. The high-calcium rats had a higher renal blood flow (7.8±0.5% vs. 6.2±0.4% cardiac output; p<0.05) and lower renal (14.3±1 vs. 19.3±2 mm Hg/min/ml/g tissue; p<0.05) and jejunal vascular resistance than did the normal calcium rats. Two additional identical groups of normal calcium- and high-calcium-DOC-salt rats (n=12 each) were also studied. In these rats, serum-ionized calcium decreased significantly (p<0.05) from baseline in both groups. Urinary sodium increased in both groups but did not differ significantly. In conclusion, dietary calcium supplementation attenuates the rise in peripheral vascular resistance that accompanies DOC-salt hypertension. This attenuated resistance appears to be relatively selective and is noted particularly in the renal vasculature.

Original languageEnglish (US)
Pages (from-to)77-82
Number of pages6
JournalHypertension
Volume13
Issue number1
DOIs
StatePublished - Jan 1989

Keywords

  • Blood pressure
  • Calcium
  • Mineralocorticoid hypertension
  • Mineralocorticoids
  • Renal blood flow
  • Sodium

ASJC Scopus subject areas

  • Internal Medicine

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