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Exogenous 25-hydroxycholecalciferol does not attenuate salt-induced hypertension
M Thierry-Palmer1, T K Tewolde, M Wang
1Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA. thierrm@link.msm.edu
The Journal of Steroid Biochemistry and Molecular Biology
|January 8, 1999
Summary
Exogenous 25-hydroxyvitamin D did not lower blood pressure in salt-sensitive rats. High salt intake accelerated vitamin D metabolism, suggesting a link between salt, vitamin D, and hypertension.
Area of Science:
- Endocrinology
- Cardiovascular Physiology
- Nutritional Science
Background:
- An inverse relationship between blood pressure and plasma 25-hydroxyvitamin D was observed in Dahl salt-sensitive rats on a high salt diet.
- Plasma 25-hydroxyvitamin D levels decreased as blood pressure increased over time.
Purpose of the Study:
- To investigate if exogenous 25-hydroxycholecalciferol could attenuate the blood pressure increase in salt-sensitive rats fed a high salt diet.
- To determine the effect of vitamin D repletion on salt-induced hypertension.
Main Methods:
- Dahl salt-sensitive rats were fed a high salt diet and administered varying doses of exogenous 25-hydroxycholecalciferol via Alzet pumps.
- Experiments were conducted on both vitamin D-replete and vitamin D-depleted rats.
- Plasma 25-hydroxyvitamin D concentrations and blood pressure were monitored.
Main Results:
- Exogenous 25-hydroxycholecalciferol had no significant effect on blood pressure in vitamin D-replete rats on a high salt diet.
- In vitamin D-depleted rats, plasma 25-hydroxyvitamin D levels were dose-proportional on a low salt diet but not on a high salt diet.
- On a high salt diet, plasma 25-hydroxyvitamin D levels were inversely proportional to blood pressure, suggesting accelerated metabolism or clearance.
Conclusions:
- Exogenous 25-hydroxycholecalciferol does not ameliorate salt-induced hypertension in Dahl salt-sensitive rats.
- Salt-induced hypertension is associated with accelerated metabolism and/or clearance of 25-hydroxyvitamin D.
- These findings highlight a complex interaction between salt intake, vitamin D status, and blood pressure regulation.
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