High dietary salt does not significantly affect plasma 25-hydroxyvitamin D concentrations of Sprague Dawley rats
1 Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, 720 Westview Dr. S.W., Atlanta, Georgia 30310-1495, USA
2 Department of Physiology, Morehouse School of Medicine, 720 Westview Dr. S.W., Atlanta, Georgia 30310-1495, USA
3 Department of Pharmacology and Toxicology, Morehouse School of Medicine, 720 Westview Dr. S.W., Atlanta, Georgia 30310-1495, USA
BMC Research Notes 2010, 3:332 doi:10.1186/1756-0500-3-332Published: 9 December 2010
The Dahl salt-sensitive rat, but not the Dahl salt-resistant rat, develops hypertension and hypovitaminosis D when fed a high salt diet. Since the salt-sensitive rat and salt-resistant rat were bred from the Sprague Dawley rat, the aim of this research was to test the hypothesis that salt-resistant and Sprague Dawley rats would be similar in their vitamin D endocrine system response to high salt intake.
Sprague Dawley, salt-sensitive, and salt-resistant rats were fed high (80 g/kg, 8%) or low (3 g/kg, 3%) salt diets for three weeks. The blood pressure of Sprague Dawley rats increased from baseline to week 3 during both high and low salt intake and the mean blood pressure at week 3 of high salt intake was higher than that at week 3 of low salt intake (P < 0.05). Mean plasma 25-hydroxyvitamin D concentrations (marker of vitamin D status) of Sprague Dawley, salt-sensitive, and salt-resistant rats were similar at week 3 of low salt intake. Mean plasma 25-hydroxyvitamin D concentrations of Sprague Dawley and salt-resistant rats were unaffected by high salt intake, whereas the mean plasma 25-hydroxyvitamin D concentration of salt-sensitive rats at week 3 of high salt intake was only 20% of that at week 3 of low salt intake.
These data indicate that the effect of high salt intake on the vitamin D endocrine system of Sprague Dawley rats at week 3 was similar to that of salt-resistant rats. The salt-sensitive rat, thus, appears to be a more appropriate model than the Sprague Dawley rat for assessing possible effects of salt-sensitivity on vitamin D status of humans.