Systemic and regional hemodynamic effects of 1,25-dihydroxyvitamin D3 administration

A. Roca-Cusachs, D. J. DiPette, J. Carson, G. A. Graham, O. B. Holland

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Abstract

Objective: To evaluate the cardiovascular effects of 1,25-dihydroxyvitamin D3 (1,25-D). Design: Recent studies suggest that Ca-regulating hormones may contribute to the genesis of hypertension. We determined systemic and regional hemodynamics 24h after administration of 1,25-D or vehicle to normal conscious Sprague Dawley rats. In addition, to dissociate the vascular effects of 1 25-D from changes in serum ionized Ca2+, 1,25-D and vehicle were administered to rats maintained for 3 days on a low-Ca diet. To evaluate the effect of the slight rise in serum ionized Ca2+ with 1,25-D administration, we infused CaCl or vehicle over 1 h into normal rats to raise the serum Ca2+ to near that of rats treated with 1,25-D. Methods: The radioactive microsphere technique was used. Results: Systemic hemodynamics (blood pressure, heart rate, cardiac output, total peripheral resistance and stroke volume) did not differ between the two groups receiving a normal-Ca diet. In these rats 1,25-D significantly decreased renal blood flow (RBF), increased renal vascular resistance (RVR) and slightly increased serum ionized Ca2+. Similarly, in rats receiving a low-Ca diet, 1,25-D administration decreased renal blood flow, increased renal vascular resistance and caused only a minimal increase in serum ionized Ca2+. A low-Ca diet also increased heart rate, cardiac blood flow and renal blood flow. Although CaCl infusion raised serum ionized Ca2+, blood pressure, renal blood flow and renal vascular resistance did not change significantly. Conclusion: 1,25-D may constrict the renal vasculature directly or indirectly by enhancing the vascular sensitivity to circulating vasoconstrictors.

Original languageEnglish (US)
Pages (from-to)939-947
Number of pages9
JournalJournal of Hypertension
Volume10
Issue number9
StatePublished - 1992

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ASJC Scopus subject areas

  • Endocrinology
  • Internal Medicine

Cite this

Roca-Cusachs, A., DiPette, D. J., Carson, J., Graham, G. A., & Holland, O. B. (1992). Systemic and regional hemodynamic effects of 1,25-dihydroxyvitamin D3 administration. Journal of Hypertension, 10(9), 939-947.