Direct derivatization of sulphate esters for analysis by gas chromatography mass spectrometry

Murray, Stephen A.; Baillie, Thomas A.

doi:10.1002/bms.1200060209

Cited by 32 publications

(10 citation statements)

References 18 publications

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“…Analyses of sulfated steroids after extraction and solvolysis have found high concentrations of DHEAS and pregnenolone sulfate in rodent and human brains [68; 69; 165; 327]. Recent studies that measure intact sulfated compounds without deconjugation [113; 124; 125; 126; 179; 180; 203] or a protocol incorporating a solid-phase extraction column purification step and simultaneous hydrolysis/derivatization with heptafluorobutyric anhydride [176; 218] have found neither DHEAS nor pregnenolone sulfate present in abundant quantities in rodent brains. For example, DHEAS was not detected in the brains of either Sprague-Dawley rats or Swiss mice (less than 0.3 ng/g) [176; 180].…”

Section: Relative Dhea(s) Concentrations In Brain Vs Plasma Vs Cmentioning

confidence: 99%

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

Maninger

Wolkowitz

Reus

et al. 2009

Frontiers in Neuroendocrinology

633

603

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DHEA and DHEAS are steroids synthesized in human adrenals, but their function is unclear. In addition to adrenal synthesis, evidence also indicates that DHEA and DHEAS are synthesized in the brain, further suggesting a role of these hormones in brain function and development. Despite intensifying research into the biology of DHEA and DHEAS, many questions concerning their mechanisms of action and their potential involvement in neuropsychiatric illnesses remain unanswered. We review and distill the preclinical and clinical data on DHEA and DHEAS, focusing on (i) biological actions and putative mechanisms of action, (ii) differences in endogenous circulating concentrations in normal subjects and patients with neuropsychiatric diseases, and (iii) the therapeutic potential of DHEA in treating these conditions. Biological actions of DHEA and DHEAS include neuroprotection, neurite growth, and antagonistic effects on oxidants and glucocorticoids. Accumulating data suggest abnormal DHEA and/or DHEAS concentrations in several neuropsychiatric conditions. The evidence that DHEA and DHEAS may be fruitful targets for pharmacotherapy in some conditions is reviewed.

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Section: Relative Dhea(s) Concentrations In Brain Vs Plasma Vs Cmentioning

confidence: 99%

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

Maninger

Wolkowitz

Reus

et al. 2009

Frontiers in Neuroendocrinology

633

603

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“…Simultaneous hydrolysis/ derivatization of PREG-S and DHEA-S with HFBA was investigated. Touchstone and Dobbins (31) reported that some sulfated steroids can react with HFBA for their conversion into heptafluorobutyrates suitable for GC-MS analysis, and Murray and Baillie (32) showed that this single-step reaction was quantitative only in the case of aromatic sulfated steroids and steroids with a 3 ␤ -sulfoxy-⌬ 5 structure, such as PREG-S and DHEA-S. The potential usefulness of this reaction was of interest because of its simplicity and the selectivity of the hydrolysis/acylation reaction.…”

Section: Derivatization Reactionmentioning

confidence: 99%

Novel lipoidal derivatives of pregnenolone and dehydroepiandrosterone and absence of their sulfated counterparts in rodent brain

Lière

Pianos

Eychenne

et al. 2004

Journal of Lipid Research

110

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A new sample preparation method coupled to GC-MS analysis was developed and validated for quantification of sulfate esters of pregnenolone (PREG-S) and dehydroepiandrosterone (DHEA-S) in rat brain. Using a solid-phase extraction recycling protocol, the results show that little or no PREG-S and DHEA-S ( Ͻ 1 pmol/g) is present in rat and mouse brain. These data are in agreement with studies in which steroid sulfates were analyzed without deconjugation. We suggest that the discrepancies between analyses with and without deconjugation are caused by internal contamination of brain extract fractions, supposed to contain steroid sulfates, by lipoidal forms of PREG and DHEA (L-PREG and L-DHEA, respectively). These derivatives can be acylated very efficiently with heptafluorobutyric anhydride and triethylamine, and their levels in rodent brain ( ‫ف‬ 1 nmol/g) are much higher than those of their unconjugated counterparts. They are distinct from fatty acid esters, and preliminary data do not favor structures such as sulfolipids or sterol peroxides. Noncovalent interactions between steroids and proteolipidic elements, such as lipoproteins, could account for some experimental data. Given their abundance in rodent brain, the structural characterization and biological functions of L-PREG and L-DHEA in the central nervous system merit considerable attention. Four years ago, we developed and validated an analytical procedure for measuring trace amounts of neurosteroids in brain tissue by GC-MS (1). This method, which includes solid-phase extraction (SPE) and HPLC as fractionation and purification steps, is very suitable for quantifying simultaneously numerous neurosteroids in small individual regions of the central nervous system (CNS) (2) or peripheral nervous system (3) with high sensitivity and accuracy. Interest was primarily focused on pregnenolone (PREG), dehydroepiandrosterone (DHEA), and their sulfated conjugates (PREG-S and DHEA-S, respectively) and on progesterone (PROG) and allopregnanolone (3 ␣ -hydroxy-5 ␣ -pregnan-20-one).Neurosteroids are synthesized by glial cells and neurons from cholesterol or from blood-borne precursors (4). In particular, PREG-S and DHEA-S are known to be neuroactive, and their major effects are the modulation of several neuronal membrane receptors, such as ␥ -aminobutyric acid (5, 6), N -methyl-d -aspartate (7), and σ receptors, by affecting neuronal excitability and behavior (8, 9). Notably, a physiologic function of PREG-S was suggested by the positive correlation between PREG-S levels in the hippocampus of aged rats and their spatial memory performance (10). However, some studies do not favor the concept that PREG-S and DHEA-S are actually neurosteroids. Indeed, contradictory results have been obtained concerning the presence and activity of the hydroxysteroid sulfotransferase, implied in the sulfation of free steroid.

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“…However, the extraction methodologies used do not usually recover the hydrophilic sulfate and glucuronide conjugates of these acids. Extraction of the conjugates would have resulted in overestimation of the "free" fraction because derivatization for gas chromatography would lead to deconjugation (17). The presence of DOPAC conjugates in human urine was reported by O'Gorman et al (9) in patients receiving L-DOPA.…”

Section: Discussionmentioning

confidence: 97%

Conjugated Versus “Free” Acidic Metabolites of Catecholamines in Random Urine Samples: Significance for the Diagnosis of Neuroblastoma

Tuchman

Stoeckeler

1988

Pediatr Res

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ABSTRACT. Random urine samples were obtained from 31 patients with neuroblastoma (newborn to 8 yr of age) and from PO0 children without this tumor (newborn to 10 yr). The urine samples were studied for the presence of sulfate and glucuronide conjugates of homovanillic (HVA), dihydroxyphenylacetic, vanilmandelic, and vanillactic acids. The urinary concentrations of these acids were determined by capillary gas-chromatography before and after enzymatic treatment with glucuronidase and sulfatase. Concentrations of the "free" fraction and "total" urinary content of these acids were determined using the results from untreated and treated urines respectively. Age-related reference values were established for children without neuroblastoma. Fractions of the total content of urinary HVA (18-39%) and dihydroxyphenylacetic acid (36-66%) were excreted as glucuronides and/or sulfates by the control group, with the highest conjugated fractions found in the urine of young infants (0-3 months). Vanilmandelic was excreted mainly as "free" acid (unconjugated), whereas vanillactic acid was undetectable in almost all control samples. Patients with neuroblastoma also excreted a fraction of these acids as glucuronide and/or sulfate conjugates, (25% of urinary HVA, 39% of dihydroxyphenylacetic acid and 45% of vanillactic acid) whereas vanilmandelic acid was excreted only as "free" in controls. Determination of "total" rather than "free" urinary HVA was diagnostic in one neuroblastoma patient with borderline "free" HVA levels, whereas determination of "free" or "total" dihydroxyphenylacetic acid and vanillactic acid did not improve the diagnostic sensitivity in the cases examined. We conclude that it may be clinically useful to determine "total" urinary HVA in patients with borderline "free" HVA levels who are suspected of having neuroblastoma. (Pediatr Res 23: 576-579,1988) Abbreviations HVA, homovanillic acid DOPAC, 3,4-dihydroxyphenylacetic acid VMA, vanilmandelic acid VLA, vanillactic acid UCr, urinary creatinine concentration Most children with neuroblastoma excrete higher than normal amounts of catecholamine metabolites in their urine (1-3). The measurement of urinary catecholamine metabolites has been used routinely to establish or confirm the diagnosis of this tumor (4, 5). Three main groups of catecholamine metabolites have been found in elevated concentrations in the urines of neuroblastoma patients I) acidic derivatives including HVA, VMA, DOPAC, and VLA; 2) Alcoholic derivatives including: 4-hydroxy-3-methoxyphenylethylglycol (HMPG) 3,4 dihydroxyphenylethylglycol; and 3) metanephrines. Of the metabolites listed above, HVA and VMA are used most often as neuroblastoma markers because they are excreted most consistently in elevated amounts by patients with neuroblastoma (5). Of patients with neuroblastoma 92% have elevated concentrations of HVA and/ or VMA in random urine samples at diagnosis (6). The use of prolonged urine collections rather than random urine samples is not advantageous in respect of diagnostic sensitivit...

show abstract

Direct derivatization of sulphate esters for analysis by gas chromatography mass spectrometry

Cited by 32 publications

References 18 publications

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

Novel lipoidal derivatives of pregnenolone and dehydroepiandrosterone and absence of their sulfated counterparts in rodent brain

Conjugated Versus “Free” Acidic Metabolites of Catecholamines in Random Urine Samples: Significance for the Diagnosis of Neuroblastoma

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