ArticleThe Journal of clinical endocrinology and metabolism2022
Circulating Conjugated and Unconjugated Vitamin D Metabolite Measurements by Liquid Chromatography Mass Spectrometry.
Article in The Journal of clinical endocrinology and metabolism, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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Who cites it
20 citing papers in PubMed, 29 citations in OpenAlex.
- Interlaboratory comparison with a reference measurement procedure (RMP) for determining 24,25-dihydroxyvitamin DAnalytical and bioanalytical chemistry · 2026Article
- Genome-wide gene-environment interaction study uncovers 162 vitamin D status variants using a precise ambient UVB measure.Nature communications · 2025Article
- The Quantification of Vitamin D in Humans: A Promising, Non-Invasive and Cost-Effective Method to Measure 25-Hydroxyvitamin D.Biomolecules · 2025Article
- Vitamin D Status and Incidence of SARS-CoV-2 Reinfections in the Borriana COVID-19 Cohort: A Population-Based Prospective Cohort Study.Tropical medicine and infectious disease · 2025Article
- Sulfation pathways in times of change.Essays in biochemistry · 2024Article
- Sulfation pathways in the maintenance of functional beta-cell mass and implications for diabetes.Essays in biochemistry · 2024Review
- Evolutionary formation of melatonin and vitamin D in early life forms: insects take centre stage.Biological reviews of the Cambridge Philosophical Society · 2024Review
- Sulfated vitamin D metabolites represent prominent roles in serum and in breastmilk of lactating women.Clinical nutrition (Edinburgh, Scotland) · 2024Article
- Calcifediol or Corticosteroids in the Treatment of COVID-19: An Observational Study.Nutrients · 2024Observational
- Current status of vitamin DFrontiers in pediatrics · 2024Article
- Analysis of vitamin DJournal of chromatography. B, Analytical technologies in the biomedical and life sciences · 2024Article
- Determination of 24,25-dihydroxyvitamin DThe Journal of steroid biochemistry and molecular biology · 2023Article
- Separation and identification of monoglucuronides of vitamin DAnalytical sciences : the international journal of the Japan Society for Analytical Chemistry · 2023Article
- The plasma free fraction of 25-hydroxyvitamin DThe Journal of steroid biochemistry and molecular biology · 2023Article
- There is more to life than serum vitamin D: a lesson from the past.Clinical science (London, England : 1979) · 2022Article
- Autoimmune disease and interconnections with vitamin D.Endocrine connections · 2022Review
- Analytical considerations for accurately capturing the relevant species contributing to vitamin D status in liquid chromatography-tandem mass spectrometry assays.Analytical science advances · 2022Article
- Circulating Conjugated and Unconjugated Vitamin D Metabolite Measurements by Liquid Chromatography Mass Spectrometry.The Journal of clinical endocrinology and metabolism · 2022Article
- Editorial: Sulfation Pathways-There and Back Again.Frontiers in molecular biosciences · 2022Article
- Profiling Urinary Sulfate Metabolites With Mass Spectrometry.Frontiers in molecular biosciences · 2022Article
Corrections and comments
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Authors and funding
6 authors at 3 institutions in 2 countries.
Funding
Abstract
contextVitamin 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.
objectiveIn this study we analyzed the contribution of sulfate and glucuronide vitamin D metabolites relative to unconjugated levels in human serum.
methodsAn 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, categorized by vitamin D supplementation status, to evaluate the proportions of each conjugated and unconjugated fraction.
resultsAs a proportion of total circulating vitamin D metabolites, sulfate conjugates (ranging between 18% and 53%) were a higher proportion than glucuronide conjugates (ranging between 2.7% and 11%). The proportion of conjugated 25OHD3 (48 ± 9%) was higher than 25OHD2 conjugates (29.1 ± 10%) across all supplementation groups. Conjugated metabolites correlated with their unconjugated forms for all 4 vitamin D metabolites (r = 0.85 to 0.97).
conclusionSulfated 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 suggest a combination of both conjugated and unconjugated measurements may provide a more accurate assessment of vitamin D status.
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