A Method for Assay of Serum or Plasma Concentrations of 1,25-Dihydroxyvitamin D

1983 ◽  
pp. 85-98
Author(s):  
Richard W. Gray
Keyword(s):  
Plasma Concentrations ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Measurement of Plasma 1,25 Dihydroxyvitamin D Using a Novel Immunoextraction Technique and Immunoassay with Iodine Labelled Vitamin D Tracer

1997 ◽  
Vol 34 (6) ◽  
pp. 632-637 ◽  
Author(s):  
W D Fraser ◽  
B H Durham ◽  
J L Berry ◽  
E B Mawer
Keyword(s):  
Vitamin D ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Sample Volume ◽  
Cross Reactivity ◽  
Regression Equations ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
High Concentrations

We evaluated a novel assay for the measurement of 1,25 dihydroxyvitamin D (1,25 (OH)2D). Immunoextraction of 1,25 (OH)2D is performed using a mini column containing a solid-phase monoclonal antibody followed by radioimmunoassay (RIA) using an 125I-labelled 1,25 (OH)2D derivative tracer and Sac-cell separation. The mean recovery of 1,25(OH)2D3 was 101%, linearity was excellent, inter- and intra-assay coefficients of variation were 9, 8 and 13% and 11, 10 and 14% at low, medium and high concentrations of 1,25(OH)2D3, respectively. The cross-reactivity of vitamin D metabolites was <0·0015% for 25-hydroxyvitamin D3, 24, 25 dihydroxyvitamin D3 and dihydrotachysterol and 0·54% for lα calcidol. 1,25 dihydroxyvitamin D2 cross-reactivity was 79%. The detection limit of the assay was 5pmol/L. Comparison with a commercial radio receptor assay (RRA) and an in-house RIA gave regression equations of y = 0·94x+11·8 ( r = 0·98) and y = 0·91x-1·7 ( r = 0.95), respectively, with no major discrepancies between the methods in all patient groups studied. Plasma concentrations of 1,25 (OH)2D obtained with the assay were as follows: normal, unsupplemented subjects: mean 88, range 48–155 pmol/L, n = 68, patients with chronic renal failure: mean 11, range 3–36 pmol/L, n = 27, primary hyperparathyroidism: mean 198, range 130–299 pmol/L, n = 23, Paget's disease: mean 92, range 42–149 pmol/L, n = 24, osteomalacia: mean 43, range 27–61 pmol/L, n = 9. A minimum sample volume of 300 μL is required, the hands-on time is significantly less than other commercial assays and the measuring procedure is gamma counting rather than scintillation counting. The assay offers several advantages over previous methods and should allow more laboratories to offer measurement of 1,25 (OH)2D as part of their repertoire.

Early effects of ethinyloestradiol and norethisterone treatment in post-menopausal women on bone resorption and calcium regulating hormones

1985 ◽  
Vol 69 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Peter L. Selby ◽  
Munro Peacock ◽  
Stuart A. Barkworth ◽  
Wendy B. Brown ◽  
Geoffrey A. Taylor
Keyword(s):  
Bone Resorption ◽  
Plasma Levels ◽  
Plasma Concentrations ◽  
Vitamin D Binding Protein ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Menopausal Women ◽  
Early Effects ◽  
Post Menopausal ◽  
Free Plasma

1. The early effects of sex steroid therapy were assessed in 28 normal post-menopausal women, 18 treated with ethinyloestradiol and 10 with norethisterone. 2. There was a reduction in the fasting urinary excretion of both calcium and hydroxyproline with both treatments, indicating reduced bone resorption. This was apparent after 1 week of therapy but became more marked after 3 weeks. 3. These changes were not accompanied by any changes in plasma levels of calcitonin or parathyroid hormone. 4. Patients receiving ethinyloestradiol showed a marked increase in plasma 1,25-dihydroxyvitamin D (1,25-(OH)2D) concentration but this was explicable entirely in terms of increased plasma levels of vitamin D binding protein. There was no change in the free plasma level of 1,25(OH)2D. Patients treated with norethisterone showed no increase in plasma concentrations of 1,25(OH)2D. 5. We conclude that both ethinyloestradiol and norethisterone have a rapid and similar effect in reducing bone resorption. This is not mediated via the plasma levels of the calcium regulating hormones.

Calcium transport in small intestine during pregnancy and lactation

1980 ◽  
Vol 239 (1) ◽  
pp. E64-E68 ◽  
Author(s):  
B. P. Halloran ◽  
H. F. DeLuca
Keyword(s):  
Vitamin D ◽  
Reproductive Cycle ◽  
Calcium Transport ◽  
Plasma Concentrations ◽  
Dihydroxyvitamin D ◽  
Control Value ◽  
1,25 Dihydroxyvitamin D ◽  
Everted Gut Sac ◽  
Pregnancy And Lactation ◽  
Active Calcium

The factors involved in calcium homeostasis during the mammalian reproductive cycle and specifically in the control of active calcium transport in the intestine have not been thoroughly investigated. For this reason calcium transport in the intestine was measured in vitamin D-replete and vitamin D-deficient rats during pregnancy and lactation using the everted gut sac technique. In addition the changes in the plasma concentrations of calcium and 1,25-dihydroxyvitamin D were measured and correlated with transport. During the later stages of pregnancy and during lactation, the concentration of calcium in the plasma is reduced 10-30%. In turn, in the vitamin D-replete rat, the concentration of 1,25-dihydroxyvitamin D in the plasma increases from a control value of 26 pg/ml to 158 pg/ml at day 14 of lactation. Calcium transport in the intestine increases late in pregnancy, peaks during lactation, and then falls to control values by 3 wk postweaning in both vitamin D-replete and D-deficient animals. These findings strengthen the established relationship between 1,25-dihydroxyvitamin D and active calcium transport in the intestine as well as suggest that some factor(s) independent of vitamin D is stimulating intestinal calcium transport during the reproductive cycle.

scholarly journals Changes in plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D during pregnancy: a Brazilian cohort

2017 ◽  
Vol 57 (3) ◽  
pp. 1059-1072 ◽  
Author(s):  
Amanda C. Cunha Figueiredo ◽  
Paula Guedes Cocate ◽  
Amanda R. Amorim Adegboye ◽  
Ana Beatriz Franco-Sena ◽  
Dayana R. Farias ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Brazilian Cohort

scholarly journals Strontium absorption and excretion in normocalciuric subjects: relation tocalcium metabolism

1998 ◽  
Vol 44 (3) ◽  
pp. 586-590 ◽  
Author(s):  
Giuseppe Vezzoli ◽  
Ivano Baragetti ◽  
Simona Zerbi ◽  
Andrea Caumo ◽  
Laura Soldati ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Kidney Stones ◽  
Stepwise Regression ◽  
Renal Excretion ◽  
Plasma Concentrations ◽  
Time Curve ◽  
Renal Handling ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Concentration Time

Abstract The relationships of Sr intestinal absorption and renal excretion with biohumoral factors regulating Ca metabolism were studied in 47 normocalciuric subjects with Ca kidney stones. Sr concentrations were measured in serum and urine after an oral load of stable Sr (30.2 μmol/kg body wt). Enteral absorption of the ion (9.77 ± 0.438 mmol · L−1 · min, 240 min after Sr administration), expressed as the area under the plasma concentration–time curve (AUC), and renal clearance (CRE) in these subjects during the test (2.80 ± 0.336 mL/min) were not different from values for 27 controls. CRE was not correlated with AUCs. Plasma concentrations of parathyroid hormone (PTH) negatively correlated with AUCs (P &lt;0.01) and correlated with CRE after one outlier was excluded (P &lt;0.05). Plasma concentrations of 1,25-dihydroxyvitamin D correlated positively with AUCs (P &lt;0.01) when normalized to the plasma concentration of PTH. Multiple stepwise regression showed that PTH and phosphatemia were significantly related to AUC values at 240 min (P &lt;0.01). These findings suggest that Sr absorption and excretion reflect the regulation of Ca metabolism, but some differences in renal handling of the two ions may exist.

Effect of Dibutyryl Adenosine 3′,5′-Monophosphate Administration on Plasma Concentrations of 1,25-Dihydroxyvitamin D in Pseudohypoparathyroidism Type I*

1981 ◽  
Vol 53 (5) ◽  
pp. 1096-1100 ◽  
Author(s):  
KANJI YAMAOKA ◽  
YOSHIKI SEINO ◽  
MAKOTO ISHIDA ◽  
TSUNEYASU ISHII ◽  
TSUNESUKE SHIMOTSUJI ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Type I ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

PLASMA 1,25-DIHYDROXYVITAMIN D LEVELS IN PREGNANCY AND LACTATION

1979 ◽  
Vol 92 (2) ◽  
pp. 330-335 ◽  
Author(s):  
Bjarne Lund ◽  
Anders Selnes
Keyword(s):  
Calcium Absorption ◽  
Plasma Concentrations ◽  
Serum Prolactin ◽  
Serum Parathyroid Hormone ◽  
Human Pregnancy ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Causative Relationship ◽  
Pregnancy And Lactation ◽  
In Pregnancy

ABSTRACT Plasma concentrations of 1,25-dihydroxyvitamin D (1,25–(OH)2D), serum prolactin and serum parathyroid hormone (PTH) were followed during pregnancy and lactation in 16 women. High 1,25–(OH)2D was demonstrated in human pregnancy and lactation. A causative relationship between 1,25–(OH)2D and prolactin is discussed and a possible explanation of the mechanism of the augmented calcium absorption in human pregnancy and lactation is suggested.

Plasma concentrations of vitamin D metabolites in pubertal girls with anorexia nervosa

1986 ◽  
Vol 113 (4_Suppl) ◽  
pp. S458-S467 ◽  
Author(s):  
D. AARSKOG ◽  
L. AKSNES ◽  
T. MARKESTAD ◽  
O. TRYGSTAD
Keyword(s):  
Vitamin D ◽  
Anorexia Nervosa ◽  
Binding Protein ◽  
Plasma Concentrations ◽  
Similar Data ◽  
Vitamin D Binding Protein ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

ABSTRACT Plasma concentrations of 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D (1,25-(OH)2D), 24,25-dihydroxyvitamin D (24,25-(OH)2D) and vitamin D-binding protein (DBP) were measured in 12 pubertal girls (aged 10-18 yr) with anorexia nervosa in relapse. The results were compared with similar data obtained in 81 healthy girls representing all stages of puberty. The patients with anorexia nervosa had significantly lower 1,25-(OH)2D levels (71 vs. 124 pmol/l; p<0.0005), and significantly higher 24,25-(OH)2D levels (6.0 vs. 3.2 nmol/l; p<0.0005), whereas the 25-OHD concentrations were similar in the two groups (85.7 vs. 86.7 nmol/l). The molar ratios of 24,25-(OH)2D to 25-OHD, which reflects the relative activity of the 24-hydroxylation, were significantly higher in the anorectics (6.6 % vs. 3.6 %; p<0.0005). The mean level of DBP did not differ between the two groups, and accordingly the calculated "free-fraction of 1,25-(OH)2 D" was significantly lower in the anorectic patients (p<0.0005). It appears that the regulatory mechanisms of the vitamin D endocrine system are altered in the patients with anorexia nervosa at puberty resulting in a relative decrease of the plasma concentration of 1,25-(OH)2D and increase of the 24,25-(OH)2D concentration. Key words: Anorexia nervosa, vitamin D metabolism, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D, vitamin D binding protein

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