High dietary cholecalciferol increases plasma 25-hydroxycholecalciferol concentration, but does not attenuate the hypertension of Dahl salt-sensitive rats fed a high salt diet.
The Dahl salt-sensitive rat, a model for salt-induced hypertension, develops hypovitaminosis D during high salt intake, which is caused by loss of protein-bound vitamin D metabolites into urine. We tested the hypothesis that high dietary cholecalciferol (5- and 10-fold standard) would increase plasma 25-hydroxycholecalciferol (25-OHD(3)) concentration (indicator of vitamin D status) of salt-sensitive rats during high salt intake. Salt-sensitive rats were fed 0.3% salt (low salt, LS), 3% salt (HS), 3% salt and 7.5 microg cholecalciferol/d (HS-D5), or 3% salt and 15 microg cholecalciferol/d (HS-D10) and sacrificed at week 4. Plasma 25-OHD(3) concentrations of the two groups of HS-D rats were similar to that of LS rats and more than twice that of HS rats. Urinary cholecalciferol metabolite content of HS-D rats was more than seven times that of HS rats. Systolic blood pressures of the hypertensive HS and HS-D rats did not significantly differ, whereas LS rats were not hypertensive. We conclude that high dietary cholecalciferol increases plasma 25-OHD(3) concentration, but does not attenuate the hypertension of salt-sensitive rats during high salt intake. Low salt intake may be necessary to both maintain optimal vitamin D status and prevent hypertension in salt-sensitive individuals.
Thierry-Palmer
Myrtle
M
Department of Microbiology, Immunology, and Biochemistry, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310, USA. mthierry-palmer@msm.edu
Cephas
Stacy
S
Muttardy
Farah F
FF
Al-Mahmoud
Ahmad
A
D000818:Animals; D002112:Calcifediol / Q000097:blood*; D002762:Cholecalciferol / Q000378:metabolism* / Q000652:urine; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D006973:Hypertension / Q000209:etiology* / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000097:blood; D051381:Rats; D020303:Rats, Inbred Dahl; D017673:Sodium Chloride, Dietary / Q000494:pharmacology*; D013997:Time Factors
D010281:Parathyroid Hormone; D017673:Sodium Chloride, Dietary; D002762:Cholecalciferol; D002112:Calcifediol