Affinity differences for vitamin D metabolites associated with the genetic isoforms of the human serum carrier protein (DBP)

1993 ◽  
Vol 92 (2) ◽  
Author(s):  
J. Arnaud ◽  
J. Constans
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Carrier Protein ◽  
Vitamin D Metabolites

scholarly journals Development and Certification of a Standard Reference Material for Vitamin D Metabolites in Human Serum

2011 ◽  
Vol 84 (2) ◽  
pp. 956-962 ◽  
Author(s):  
Karen W. Phinney ◽  
Mary Bedner ◽  
Susan S.-C. Tai ◽  
Veronica V. Vamathevan ◽  
Lane C. Sander ◽  
...  
Keyword(s):  
Vitamin D ◽  
Reference Material ◽  
Human Serum ◽  
Standard Reference Material ◽  
Vitamin D Metabolites

Simultaneous measurement of 13 circulating vitamin D3 and D2 mono and dihydroxy metabolites using liquid chromatography mass spectrometry

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Carl Jenkinson ◽  
Reena Desai ◽  
Andrzej T. Slominski ◽  
Robert C. Tuckey ◽  
Martin Hewison ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Vitamin D ◽  
Liquid Chromatography ◽  
Human Serum ◽  
High Sensitivity ◽  
Reference Level ◽  
Vitamin D Metabolites ◽  
Serum Samples ◽  
Human Serum Samples ◽  
Limit Of Quantitation

Abstract Objectives Clinical evaluation of vitamin D status is conventionally performed by measuring serum levels of a single vitamin D metabolite, 25-hydroxyvitamin D predominantly by immunoassay methodology. However, this neglects the complex metabolic pathways involved in vitamin D bioactivity, including two canonical forms D3 and D2, bioactive 1,25-dihydroxy metabolites and inactive 24-hydroxy and other metabolites. Methods Liquid chromatography-tandem mass spectrometry (LC-MS/MS) can measure multiple analytes in a sample during a single run with high sensitivity and reference level specificity. We therefore aimed to develop and validate a LC-MS/MS method to measure simultaneously 13 circulating vitamin D metabolites and apply it to 103 human serum samples. Results The LC-MS/MS method using a Cookson-type derivatization reagent phenyl-1,2,4-triazoline-3,5-dione (PTAD) quantifies 13 vitamin D metabolites, including mono and dihydroxy-metabolites, as well as CYP11A1-derived D3 and D2 metabolites in a single run. The lower limit of quantitation was 12.5 pg/mL for 1,25(OH)2D3 with accuracy verified by analysis of National Institute of Standards and Technology (NIST) 972a standards. Quantification of seven metabolites (25(OH)D3, 25(OH)D2, 3-epi-25(OH)D3, 20(OH)D3, 24,25(OH)2D3, 1,25(OH)2D3 and 1,20S(OH)2D3) was consistently achieved in human serum samples. Conclusions This profiling method can provide new insight into circulating vitamin D metabolite pathways forming the basis for improved understanding of the role of vitamin D in health and disease.

scholarly journals Circulating conjugated and unconjugated vitamin D metabolite measurements by liquid chromatography mass spectrometry

2021 ◽  
Author(s):  
Carl Jenkinson ◽  
Reena Desai ◽  
Malcolm D McLeod ◽  
Jonathan Wolf Mueller ◽  
Martin Hewison ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Vitamin D ◽  
Liquid Chromatography ◽  
Human Serum ◽  
Phase Ii ◽  
Enzyme Hydrolysis ◽  
Vitamin D Metabolites ◽  
Vitamin D Status ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

Abstract Context Vitamin D status is conventionally defined by measurement of unconjugated circulating 25-hydroxyvitamin D (25OHD), but it remains uncertain whether this isolated analysis gives sufficient weight to vitamin D’s diverse metabolic pathways and bioactivity. Emerging evidence has shown that phase II endocrine metabolites are important excretory or storage forms, however the clinical significance of circulating phase II vitamin D metabolites remains uncertain. In this study we analysed the contribution of sulfate and glucuronide vitamin D metabolites relative to unconjugated levels in human serum. Methods An optimized enzyme hydrolysis method using recombinant arylsulfatase (Pseudomonas aeruginosa) and beta-glucuronidase (Escherichia coli) was combined with liquid chromatography mass spectrometry (LC-MS/MS) analysis to measure conjugated and unconjugated vitamin D metabolites 25OHD3, 25OHD2, 3-epi-25OHD3 and 24,25(OH)2D3. The method was applied to the analysis of 170 human serum samples from community-dwelling men aged over 70 years, categorised by vitamin D supplementation status, to evaluate the proportions of each conjugated and unconjugated fraction. Results As a proportion of total circulating vitamin D metabolites, sulfate conjugates (ranging between 18-53%) were a higher proportion than glucuronide conjugates (ranging between 2.7-11%). The proportion of conjugated 25OHD3 (48±9%) was higher compared to 25OHD2 conjugates (29.1±10%) across all supplementation groups. Conjugated metabolites correlated with their unconjugated forms for all four vitamin D metabolites (r=0.85 to 0.97). Conclusions Sulfated conjugates form a high proportion of circulating vitamin D metabolites, whereas glucuronide conjugates constitute a smaller fraction. Our findings principally in older men highlight the differences in abundance between metabolites and suggests a combination of both conjugated and unconjugated measurements may provide a more accurate assessment of vitamin D status.

CCQM-K132: low-polarity analytes in a biological matrix: vitamin D metabolites in human serum

Metrologia ◽  
2017 ◽  
Vol 54 (1A) ◽  
pp. 08027-08027
Author(s):  
Stephen A Wise ◽  
Susan S -C Tai ◽  
David L Duewer ◽  
Mary Bedner ◽  
Johanna E Camara ◽  
...  
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Vitamin D Metabolites ◽  
Biological Matrix

A simplified assay for dihydroxylated vitamin D metabolites in human serum: application to hyper- and hypovitaminosis D.

1980 ◽  
Vol 26 (3) ◽  
pp. 444-450 ◽  
Author(s):  
R S Mason ◽  
D Lissner ◽  
H S Grunstein ◽  
S Posen
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Hypovitaminosis D ◽  
Reference Interval ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Vitamin D Intoxication ◽  
25 Hydroxyvitamin D

Abstract We describe a simplified assay for 24,25-and 1.25-dihydroxyvitamin D in human serum. It involves two preparative steps, and normal chick intestine is used in preparing cytosol-binding protein. Our results for 24,25-dihydroxyvitamin D include a reference interval of 2.9—16 nmol/L (1.2—6.7 microgram/L), a mean of 6.7 nmol/L (2.8 microgram/L), an intra-assay CV of 11%, and an interassay CV of 22%. For 1,25-dihydroxyvitamin D, these data were 29—168 pmol/L (12—70 ng/L), 86 pmol/L (36 ng/L), 12%, and 22%, respectively. In hypoparathyroid patients with vitamin D intoxication, mean concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum were significantly above normal; the 1,25-dihydroxyvitamin D concentrations were significantly below normal. Patients with malabsorption and/or post-gastrectomy states had significantly subnormal values for both 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum, and there was a significantly negative correlation between each of these biochemical values and the severity of osteomalacia. We also discuss cost effectiveness of assaying vitamin D metabolites in human serum.

Development of Standard Reference Material (SRM) 2973 Vitamin D Metabolites in Frozen Human Serum (High Level)

2017 ◽  
Vol 100 (5) ◽  
pp. 1294-1303 ◽  
Author(s):  
Susan S.-C. Tai ◽  
Michael A. Nelson ◽  
Mary Bedner ◽  
Brian E. Lang ◽  
Karen W. Phinney ◽  
...  
Keyword(s):  
Vitamin D ◽  
Reference Material ◽  
Human Serum ◽  
Standard Reference Material ◽  
Vitamin D Metabolites ◽  
High Level

scholarly journals Development of an Improved Standard Reference Material for Vitamin D Metabolites in Human Serum

2017 ◽  
Vol 89 (9) ◽  
pp. 4907-4913 ◽  
Author(s):  
Karen W. Phinney ◽  
Susan S.-C. Tai ◽  
Mary Bedner ◽  
Johanna E. Camara ◽  
Rosalind R. C. Chia ◽  
...  
Keyword(s):  
Vitamin D ◽  
Reference Material ◽  
Human Serum ◽  
Standard Reference Material ◽  
Vitamin D Metabolites

Interlaboratory Comparison for the Determination of 24,25-Dihydroxyvitamin D3 in Human Serum Using Liquid Chromatography with Tandem Mass Spectrometry

2017 ◽  
Vol 100 (5) ◽  
pp. 1308-1317 ◽  
Author(s):  
Stephen A Wise ◽  
Susan S-C Tai ◽  
Michael A Nelson ◽  
Carolyn Q Burdette ◽  
Johanna E Camara ◽  
...  
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Interlaboratory Comparison ◽  
Standard Reference Materials ◽  
Vitamin D Metabolites ◽  
External Quality Assessment Scheme ◽  
Dihydroxyvitamin D3 ◽  
Laboratory Results ◽  
24,25 Dihydroxyvitamin D3

Abstract Six laboratories associated with the Vitamin D Standardization Program (VDSP) participated in an interlaboratory comparison of LC with tandem MS (MS/MS) methods for the determination of 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] in human serum. The laboratories analyzed two different serum-based Standard Reference Materials (SRMs) intended for use in the determination of 25-hydroxyvitamin D and 30 samples from the Vitamin D External Quality Assessment Scheme (DEQAS). All laboratorymethods for 24,25(OH)2D3 were based on isotope dilution LC-MS/MS; three of the methods used derivatization of the vitamin D metabolites before LC-MS/MS. Laboratory results were compared to the National Institute of Standards and Technology (NIST) results, which were obtained using their newly developed candidate reference measurement procedure for 24,25(OH)2D3. Laboratory results for the SRM samples varied in comparability to the NIST results, with one laboratory in excellent agreement (−1.6% mean bias), three laboratories at 10–15% mean bias, and the remaining laboratory at 36% mean bias. For the 30 DEQAS samples, the mean bias for the five laboratories ranged from 6 to 15%; however, the SD of the bias ranged from 8 to 29%. As a result of this intercomparison study, one laboratory discovered and corrected a methodcalculation error and another laboratory modified and improved their LC-MS/MS method.

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