The Effects of Diphosphonate on the Metabolism and Biological Activity of Vitamin D

1972 ◽  
Vol 42 (4) ◽  
pp. 16P-16P ◽  
Author(s):  
L. F. Hill ◽  
E. B. Mawer ◽  
G. A. Lumb ◽  
S. W. Stanbury
Keyword(s):  
Vitamin D ◽  
Biological Activity

scholarly journals Biological activity of 24,24-difluoro-25-hydroxyvitamin D3. Effect of blocking of 24-hydroxylation on the functions of vitamin D.

1979 ◽  
Vol 254 (15) ◽  
pp. 7163-7167
Author(s):  
Y Tanaka ◽  
H F DeLuca ◽  
Y Kobayashi ◽  
T Taguchi ◽  
N Ikekawa ◽  
...  
Keyword(s):  
Vitamin D ◽  
Biological Activity

scholarly journals Epimers of Vitamin D: A Review

2020 ◽  
Vol 21 (2) ◽  
pp. 470 ◽  
Author(s):  
Bashar Al-Zohily ◽  
Asma Al-Menhali ◽  
Salah Gariballa ◽  
Afrozul Haq ◽  
Iltaf Shah
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Hydroxyl Group ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D3 ◽  
In Vivo Models ◽  
Vitamin D Receptors ◽  
Potential Factors

In this review, we discuss the sources, formation, metabolism, function, biological activity, and potency of C3-epimers (epimers of vitamin D). We also determine the role of epimerase in vitamin D-binding protein (DBP) and vitamin D receptors (VDR) according to different subcellular localizations. The importance of C3 epimerization and the metabolic pathway of vitamin D at the hydroxyl group have recently been recognized. Here, the hydroxyl group at the C3 position is orientated differently from the alpha to beta orientation in space. However, the details of this epimerization pathway are not yet clearly understood. Even the gene encoding for the enzyme involved in epimerization has not yet been identified. Many published research articles have illustrated the biological activity of C3 epimeric metabolites using an in vitro model, but the studies on in vivo models are substantially inadequate. The metabolic stability of 3-epi-1α,25(OH)2D3 has been demonstrated to be higher than its primary metabolites. 3-epi-1 alpha, 25 dihydroxyvitamin D3 (3-epi-1α,25(OH)2D3) is thought to have fewer calcemic effects than non-epimeric forms of vitamin D. Some researchers have observed a larger proportion of total vitamin D as C3-epimers in infants than in adults. Insufficient levels of vitamin D were found in mothers and their newborns when the epimers were not included in the measurement of vitamin D. Oral supplementation of vitamin D has also been found to potentially cause increased production of epimers in mice but not humans. Moreover, routine vitamin D blood tests for healthy adults will not be significantly affected by epimeric interference using LC–MS/MS assays. Recent genetic models also show that the genetic determinants and the potential factors of C3-epimers differ from those of non-C3-epimers.Most commercial immunoassays techniques can lead to inaccurate vitamin D results due to epimeric interference, especially in infants and pregnant women. It is also known that the LC–MS/MS technique can chromatographically separate epimeric and isobaric interference and detect vitamin D metabolites sensitively and accurately. Unfortunately, many labs around the world do not take into account the interference caused by epimers. In this review, various methods and techniques for the analysis of C3-epimers are also discussed. The authors believe that C3-epimers may have an important role to play in clinical research, and further research is warranted.

Effect of Phenobarbitone Treatment on Vitamin D Metabolism in Mammals

1974 ◽  
Vol 46 (4) ◽  
pp. 433-448 ◽  
Author(s):  
J. Silver ◽  
G. Neale ◽  
G. R. Thompson
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Silicic Acid ◽  
Vitamin D3 ◽  
Water Soluble ◽  
Prolonged Treatment ◽  
Vitamin D Metabolism ◽  
Silicic Acid Chromatography ◽  
Polar Metabolites ◽  
25 Hydroxycholecalciferol

1. The metabolism of radioactive cholecalciferol was studied in control and phenobarbitone-treated rats and pigs. 2. Treatment with phenobarbitone enhanced the appearance in plasma of 25-hydroxycholecalciferol (peak IV on silicic acid chromatography), and of more-polar metabolites (peak V), but not of the most-polar metabolites (peak VI). Peak IV had the chromatographic properties of authentic 25-hydroxycholecalciferol (25-HCC) and had biological activity. 3. There was no effect on the appearance of peaks V and VI in plasma after an injection of radioactive 25-HCC. 4. Treatment with phenobarbitone enhanced the excretion of metabolites of radioactive vitamin D3 in bile. These metabolites were largely water-soluble conjugates of peaks IV, V and VI, which included glucuronides. Peak IV in bile was not identical with 25-HCC. 5. Prolonged treatment with phenobarbitone depleted the tissue radioactivity of rats given radioactive vitamin D3.

Synthesis and Biological Activity of Vitamin D Conjugates

Vitamin D ◽  
1984 ◽  
pp. 523-538
Author(s):  
S. Nagubandi ◽  
R. Kumar
Keyword(s):  
Vitamin D ◽  
Biological Activity

scholarly journals Lack of biological activity of vitamin D3-3β sulfate during lactation in vitamin D-deficient rats

1987 ◽  
Vol 27 (6) ◽  
pp. 979-997 ◽  
Author(s):  
Leonor CANCELA ◽  
P. J. MARIE ◽  
Noélie LE BOULCH ◽  
Livia MIRAVET
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Vitamin D3

Comparison of total, free and bioavailable 25-OH vitamin D determinations to evaluate its biological activity in healthy adults: the LabOscat study

2017 ◽  
Vol 28 (8) ◽  
pp. 2457-2464 ◽  
Author(s):  
P. Peris ◽  
◽  
X. Filella ◽  
A. Monegal ◽  
N. Guañabens ◽  
...  
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Healthy Adults ◽  
25 Oh Vitamin D

Synthesis and biological activity of novel vitamin D analogs: 24,24-difluoro-25-hydroxy-26,27-dimethylvitamin D3 and 24,24-difluoro-1.alpha.,25-dihydroxy-26,27-dimethylvitamin D3

1990 ◽  
Vol 33 (2) ◽  
pp. 480-490 ◽  
Author(s):  
Harpal S. Gill ◽  
James M. Londowski ◽  
Robert A. Corradino ◽  
Alan R. Zinsmeister ◽  
Rajiv Kumar
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Vitamin D Analogs

ChemInform Abstract: Synthesis and Biological Activity of Fluorinated Vitamin D

ChemInform ◽  
2010 ◽  
Vol 41 (39) ◽  
pp. no-no
Author(s):  
Toshie Fujishima ◽  
Sinya Fujii ◽  
Takashi Harayama
Keyword(s):  
Vitamin D ◽  
Biological Activity
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