Analysis of Vitamins D, Their Metabolites and Analogues

Makin, H. L. J.; Jones, Glenville; Kaufmann, Martin; Calverley, Martin J.

doi:10.1023/b135931_11

Cited by 13 publications

(19 citation statements)

References 431 publications

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“…If not, an alternative sterol oxidase must be responsible for this conversion in the Cyp27a1−/− mouse. One candidate is CYP24A1 which has been shown to catalyse similar reactions during vitamin D 3 metabolism [ 66 ].…”

Section: Discussionmentioning

confidence: 99%

Additional pathways of sterol metabolism: Evidence from analysis of Cyp27a1−/− mouse brain and plasma

Griffiths

Crick

Meljon

et al. 2019

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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Cytochrome P450 (CYP) 27A1 is a key enzyme in both the acidic and neutral pathways of bile acid biosynthesis accepting cholesterol and ring-hydroxylated sterols as substrates introducing a (25R)26-hydroxy and ultimately a (25R)26-acid group to the sterol side-chain. In human, mutations in the CYP27A1 gene are the cause of the autosomal recessive disease cerebrotendinous xanthomatosis (CTX). Surprisingly, Cyp27a1 knockout mice (Cyp27a1−/−) do not present a CTX phenotype despite generating a similar global pattern of sterols. Using liquid chromatography – mass spectrometry and exploiting a charge-tagging approach for oxysterol analysis we identified over 50 cholesterol metabolites and precursors in the brain and circulation of Cyp27a1−/− mice. Notably, we identified (25R)26,7α- and (25S)26,7α-dihydroxy epimers of oxysterols and cholestenoic acids, indicating the presence of an additional sterol 26-hydroxylase in mouse. Importantly, our analysis also revealed elevated levels of 7α-hydroxycholest-4-en-3-one, which we found increased the number of oculomotor neurons in primary mouse brain cultures. 7α-Hydroxycholest-4-en-3-one is a ligand for the pregnane X receptor (PXR), activation of which is known to up-regulate the expression of CYP3A11, which we confirm has sterol 26-hydroxylase activity. This can explain the formation of (25R)26,7α- and (25S)26,7α-dihydroxy epimers of oxysterols and cholestenoic acids; the acid with the former stereochemistry is a liver X receptor (LXR) ligand that increases the number of oculomotor neurons in primary brain cultures. We hereby suggest that a lack of a motor neuron phenotype in some CTX patients and Cyp27a1−/− mice may involve increased levels of 7α-hydroxycholest-4-en-3-one and activation PXR, as well as increased levels of sterol 26-hydroxylase and the production of neuroprotective sterols capable of activating LXR.

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Section: Discussionmentioning

confidence: 99%

Additional pathways of sterol metabolism: Evidence from analysis of Cyp27a1−/− mouse brain and plasma

Griffiths

Crick

Meljon

et al. 2019

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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“…2. ELISA estimation of serum insulin levels using ELYSA kit (Enzymuntest Insulin, ES 600, Boehringer Mannheim) (22) , ADR using ELYSA kit (MyBioSource Inc., San Diego, California, USA) (23) and FABP4 using ELYSA kit (MyBioSource Inc., San Diego, California, USA) (24) .…”

Section: Patients and Methods:-mentioning

confidence: 99%

Serum Adropin and Adipose Fatty-Acid Binding Protein at 6th Week of Pregnancy Are Significant Predictors for Development of Insulin Resistance at the 24th Week.

Sharafeldeen¹

2018

IJAR

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“…Since aqueous media are not compatible with Cookson reagent and SDS is harmful to the mass spectrometer, it is necessary to pretreat dissolution samples. Since alfacalcidol was readily soluble in dichloromethane [7], it is reported that vitamin D is soluble in cyclohexane [14], dichloromethane and cyclohexane mixture was first studied for liquid-liquid extraction. It was found that interfacial emulsification occurred during liquidliquid extraction.…”

Section: Extraction and Derivatizationmentioning

confidence: 99%

Quantification of Alfacalcidol Tablets Dissolution Content by Chemical Derivatization and LC-MS

Liu

Chen

Yuan

et al. 2020

Journal of Analytical Methods in Chemistry

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Application of liquid chromatography-mass spectrometry (LC-MS) in analyzing the content of alfacalcidol tablets dissolution faces big challenges due to the low amount of alfacalcidol in each tablet and the low ionization efficacy of the compound with electrospray ionization (ESI) or atmospheric-pressure chemical ionization (APCI). Here, extraction, derivatization, and LC-MS quantitation method have been developed and validated for measuring alfacalcidol tablets dissolution content. After alfacalcidol dissolution solution was extracted with dichloromethane to remove surfactant and inorganic salts, alfacalcidol was then derivatized via a Cookson reagent, 4-phenyl-1, 2, 4-triazoline-3, 5-dione (PTAD), under ambient conditions. Alfacalcidol derivative was successfully analyzed by LC-MS. Limit of detection (LOD) of the derivatized alfacalcidol was improved 100 times (0.01 μg/mL) compared with the nontreated compound (1 μg/mL). The new method was then validated following International Conference on Harmonization (ICH) guidance. The method shows a good linearity with r2 > 0.99. Interday and intraday reproducibility was 3.3% and 7.9%, respectively. This procedure can be used in quantification of alfacalcidol tablets dissolution content and corresponding pharmaceutical quality control.

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Analysis of Vitamins D, Their Metabolites and Analogues

Cited by 13 publications

References 431 publications

Additional pathways of sterol metabolism: Evidence from analysis of Cyp27a1−/− mouse brain and plasma

Additional pathways of sterol metabolism: Evidence from analysis of Cyp27a1−/− mouse brain and plasma

Serum Adropin and Adipose Fatty-Acid Binding Protein at 6th Week of Pregnancy Are Significant Predictors for Development of Insulin Resistance at the 24th Week.

Quantification of Alfacalcidol Tablets Dissolution Content by Chemical Derivatization and LC-MS

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