scholarly journals Multiple Fluorometric Assay of Three Major Vitamin D3 Metabolites (25-Hydroxyvitamin D3, 24,25-Dihydroxyvitamin D3 and 1,25-Dihydroxyvitamin D3) in Plasma and Its Application to Clinical Studies.

1997 ◽  
Vol 13 (2) ◽  
pp. 255-261 ◽  
Author(s):  
Xinxiang WANG ◽  
Masato SHIMIZU ◽  
Fujio NUMANO ◽  
Hiroshi ASAOKA ◽  
Sachiko YAMADA
1980 ◽  
Vol 239 (6) ◽  
pp. E515-E523 ◽  
Author(s):  
B. S. Levine ◽  
N. Brautbar ◽  
M. W. Walling ◽  
D. B. Lee ◽  
J. W. Coburn

Effects of 6-9 days of vitamin D3 (D3), 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], or 1,24,25-trihydroxyvitamin D3 [1,24,25(OH)3D3] on Mg metabolism were studied in vitamin D-deficient (-D) rats. Mg absorption expressed as percent intake increased with 1,25(OH)2D3 and 1,24,25(OH)3D3. Urinary Mg (UMg) increased with no change in serum Mg (SMg) or Mg balance. 1,25(OH)2D3 was threefold more potent than 1,24,25(OH)3D3 in raising serum Ca and Mg absorption. In a separate experiment in pair-fed rats given D3, 1,25-(OH)2D3, or 1,24,25(OH)3D3, the diet contained either 0.03 or 0.2% Mg; 1,25(OH)2D3 and D3 lowered SMg after 3 days; UMg increased after 24 h to remain elevated. D3 and 1,25(OH)2D3 augmented Mg absorption; feeding 0.2% Mg lowered Mg absorption in -D animals. All sterols augmented Mg absorption in -D rats; both the earlier action of 1,25(OH)2D3 and 1,24,25(OH)3D3 suggests that 1-hydroxylation is necessary. Suppressed Mg absorption with 0.2% Mg in -D rats suggests two transport processes, with one vitamin D dependent. Higher UMg with decreased SMg with 1,25(OH)2D3 suggests reduced tubular reabsorption.


1985 ◽  
Vol 248 (3) ◽  
pp. E281-E285 ◽  
Author(s):  
L. E. Hart ◽  
H. F. DeLuca

The biochemical nature of the physiological defect found in chick embryos from hens supported on 1,25-dihydroxyvitamin D3 as their sole source of vitamin D is described. Vitamin D-deficient hens (44-wk-old) were divided into six groups of five and dosed daily for 19 wk with either 2.0 micrograms of 25-hydroxyvitamin D3, 2.0 micrograms of 24,24-difluoro-25-hydroxy-vitamin D3, 0.4 micrograms of 1,25-dihydroxyvitamin D3, 2.0 micrograms of 24,25-dihydroxyvitamin D3, 0.4 micrograms of 1,25-dihydroxyvitamin D3 plus 2.0 micrograms of 24,25-dihydroxyvitamin D3, or vehicle only. Normal embryonic development was found in eggs from hens given 25-hydroxyvitamin D3 or 24,24-difluoro-25-hydroxyvitamin D3, whereas embryos from hens given 1,25-dihydroxyvitamin D3, 24,25-dihydroxyvitamin D3, or their combination were abnormal and failed to hatch. Embryos from hens fed 1,25-dihydroxyvitamin D3 and/or 24,25-dihydroxyvitamin D3 had vitamin D deficiency: low bone ash, low plasma calcium, low total body calcium, and extremely high plasma phosphorus. Because the shell is the major source of calcium for the developing embryo, calcium transport from the shell to the embryos across the chorioallantoic membrane apparently fails, giving rise to the observed defects in embryonic development.


1985 ◽  
Vol 260 (25) ◽  
pp. 13625-13630
Author(s):  
K Jarnagin ◽  
S Y Zeng ◽  
M Phelps ◽  
H F DeLuca

1983 ◽  
Vol 65 (4) ◽  
pp. 429-436 ◽  
Author(s):  
S. Dekel ◽  
R. Salama ◽  
S. Edelstein

1. One-day-old chicks were depleted of vitamin D. At 3 weeks their right tibiae, and those of a control group given vitamin D3, were fractured and pinned. After fracture the controls were kept on vitamin D3. Another group was left vitamin D-deficient. The remaining depleted chicks, divided into four groups, were given vitamin D3, 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or a combination of 24,25(OH)2D3 and 1,25(OH)2D3. 2. The callus obtained after 9 and 14 days was subjected to torsional stress. The callus of chicks given vitamin D continuously showed the greatest resistance, whereas that of vitamin D-deficient chicks showed the smallest resistance. Repletion with either vitamin D3 or its metabolites increased the strength of the callus. Repletion with the combination of 24,25(OH)2D3 and 1,25(OH)2D3 produced the most marked results, in that the callus was even stronger than that of chicks replete with vitamin D3. 3. It is concluded that 24,25(OH)2D3 is essential for bone formation in addition to the known active vitamin D metabolite 1,25(OH)2D3, and the possible clinical implications of these findings are discussed.


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