title: Plasma 25-hydroxyvitamin D concentrations are inversely associated with blood pressure of Dahl salt-sensitive rats.
abstract: Dietary salt is a contributing factor to the development of hypertension in individuals who are salt-sensitive. The vitamin D endocrine system has been reported to modulate vascular structure and function. Since elderly hypertensive females with low plasma renin activity, typical of salt-sensitivity, had significantly lower 25-hydroxyvitamin D concentrations compared with normotensive elderly and young females, we have used Dahl salt-sensitive and salt-resistant rats fed high (80 g/kg diet) and low (3 g/kg diet) salt diets as models to examine the relationship between salt-sensitivity and 25-hydroxyvitamin D, the precursor of the hormonal form of vitamin D, 1,25-dihydroxyvitamin D. Plasma 25-hydroxyvitamin D concentrations of salt-resistant rats were unaffected by a high salt diet, but plasma 25-hydroxyvitamin D concentrations of salt-sensitive rats were significantly reduced within three weeks to lower than 25%. There was a negative association between plasma 25-hydroxyvitamin D concentrations of salt-sensitive rats and the number of days that the rats were fed a high salt diet (r = -0.98, P < 0.02) and a positive association between blood pressure and the number of days that the rats were fed a high salt diet (r = 0.97, P < 0.05). An inverse relationship was found between plasma 25-hydroxyvitamin D concentrations and blood pressure (r = -0.99, P < 0.01). Spontaneously hypertensive rats did not have low plasma 25-hydroxyvitamin D concentrations, suggesting that reduction of plasma 25-hydroxyvitamin D concentration might be specific to salt-induced hypertension.
authors.affiliation: Department of Biochemistry, Morehouse School of Medicine, Atlanta, GA 30310-1495, USA. thierrm@link.msm.edu
authors.forename: M
authors.initials: M
authors.lastname: Thierry-Palmer
authors.forename: K S
authors.initials: KS
authors.lastname: Carlyle
authors.forename: M D
authors.initials: MD
authors.lastname: Williams
authors.forename: T
authors.initials: T
authors.lastname: Tewolde
authors.forename: S
authors.initials: S
authors.lastname: Caines-McKenzie
authors.forename: M A
authors.initials: MA
authors.lastname: Bayorh
authors.forename: N L
authors.initials: NL
authors.lastname: Emmett
authors.forename: S A
authors.initials: SA
authors.lastname: Harris-Hooker
authors.forename: G L
authors.initials: GL
authors.lastname: Sanford
authors.forename: E F
authors.initials: EF
authors.lastname: Williams
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D002112:Calcifediol / Q000097:blood*; D004039:Diet, Sodium-Restricted; D004198:Disease Susceptibility; D006973:Hypertension / Q000097:blood / Q000503:physiopathology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D012982:Sodium, Dietary; D013599:Systole
chemical_list: D012982:Sodium, Dietary; D002112:Calcifediol