title: 25-Hydroxyvitamin D3 reverses alteration of the vitamin D-endocrine system in blacks.
abstract: BACKGROUND
  Previous findings indicated that serum 25-hydroxyvitamin D and urinary calcium are decreased and serum immunoreactive parathyroid hormone, serum 1,25-dihydroxyvitamin D, and urinary cyclic adenosine 3',5'-monophosphate are increased in normal black compared to normal white subjects. Studies were carried out to determine if alteration of the vitamin D-endocrine system in blacks is reversed by oral supplementation with 25-hydroxyvitamin D3.
  
  
  METHODS
  Eight normal young adult black men and women were admitted two times to a metabolic ward for 2.5 days and studied after no treatment and again after treatment for 1 week with oral 25-hydroxyvitamin D3, 40 to 60 micrograms/d. Six of the subjects underwent a postcontrol study after discontinuation of treatment.
  
  
  RESULTS
  25-Hydroxyvitamin D3 treatment significantly increased serum 25-hydroxyvitamin D and urinary calcium and reduced serum 1,25-dihydroxyvitamin D and urinary cyclic adenosine 3',5'-monophosphate, an index of function of parathyroid hormone. In a postcontrol study, values for serum 25-hydroxyvitamin D, serum 1,25-dihydroxyvitamin D, and urinary calcium had returned to control values.
  
  
  CONCLUSIONS
  The results provide evidence that reduction of serum 25-hydroxyvitamin D contributes to or accounts for alteration of the vitamin D-endocrine system in black subjects.
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, USA.
authors.forename: N H
authors.initials: NH
authors.lastname: Bell
mesh_terms: D000284:Administration, Oral; D000328:Adult; D044383:Black People; D002112:Calcifediol / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003404:Creatinine / Q000097:blood; D000242:Cyclic AMP / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000502:physiology; D010758:Phosphorus / Q000097:blood / Q000378:metabolism* / Q000652:urine; D012016:Reference Values
chemical_list: D010281:Parathyroid Hormone; D010758:Phosphorus; D003404:Creatinine; D000242:Cyclic AMP; D002112:Calcifediol; D002118:Calcium