title: The response of Dahl salt-sensitive and salt-resistant female rats to a space flight model.
abstract: Vitamin D metabolism in the Dahl salt-sensitive (S) rat, a model of salt-induced hypertension, differs from that in the Dahl salt-resistant (R) rat. We have tested the hypothesis that differences in vitamin D metabolism would render the Dahl S rat more susceptible than the Dahl R rat to the effects of a space flight model. Dahl female rats were tail suspended (hind limb unloaded) for 28 days, while fed a low salt (3 g/kg sodium chloride) diet. Plasma 25-OHD concentrations of S rats were significantly lower than that of R rats. Plasma 1,25-(OH)2D concentration was 50% lower in unloaded than in loaded S rats, but was unaffected in unloaded R rats. The left soleus muscle weight and breaking strength of the left femur (torsion test) were 50% and 25% lower in unloaded than in loaded S and R rats. The mineral content of the left femur, however, was significantly lower (by 11%) only in unloaded S rats. We conclude that female S rats are more vulnerable than female R rats to decreases in plasma 1,25-(OH)2D concentration and femur mineral content during hind limb unloading, but equally vulnerable to muscle atrophy and reduced breaking strength of the femur.
authors.affiliation: Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310, USA. mthierrypalmer@msm.edu
authors.forename: Myrtle
authors.initials: M
authors.lastname: Thierry-Palmer
authors.forename: Stacy
authors.initials: S
authors.lastname: Cephas
authors.forename: Tammy
authors.initials: T
authors.lastname: Cleek
authors.forename: Phouyong
authors.initials: P
authors.lastname: Sayavongsa
authors.forename: Sara B
authors.initials: SB
authors.lastname: Arnaud
mesh_terms: D000818:Animals; D001835:Body Weight; D015519:Bone Density / Q000502:physiology*; D002118:Calcium / Q000097:blood / Q000652:urine; D004039:Diet, Sodium-Restricted; D004044:Dietary Proteins / Q000097:blood / Q000652:urine; D005260:Female; D005269:Femur / Q000502:physiology*; D019417:Hindlimb Suspension; D023421:Models, Animal; D018482:Muscle, Skeletal / Q000502:physiology*; D009929:Organ Size; D010281:Parathyroid Hormone / Q000097:blood / Q000652:urine; D051381:Rats; D020303:Rats, Inbred Dahl; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism* / Q000652:urine; D018474:Weightlessness Simulation
chemical_list: D004044:Dietary Proteins; D010281:Parathyroid Hormone; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium