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  • 1
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The negative ion chemical ionization mass spectra of the MO-TMS derivatives of the corticosteroids prednisolone, betamethasone and dexamethasone have been obtained using capillary column gas chromatography mass spectrometry. The spectra showed abundant diagnostic ions at m/z〉300 allowing for clear discrimination between the three steroid derivatives. A capillary column gas chromatographic mass spectrometric method using negative ion chemical ionization mass spectrometry has been developed to confirm the presence of the parent steroids in horse urine following the administration of proprietary preparations of prednisolone and betamethasone.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism and urinary excretion of 1,2(n)-3H-1-dehydrotestosterone were studied in cross-bred gelded horses. Approximately 40% of the dose was excreted in 24 h. The steroid metabolites were extracted by Amberlite XAD-2 resin and fractionated into glucuronides and sulphoconjugates. Unchanged 1-dehydrotes-tosterone was the only component identified by gas chromatography mass spectrometry after solvolysis of the sulphoconjugates. Positive and negative ion fast atom bombardment mass spectra were obtained on the purified 1-dehydrotestosterone sulphoconjugate isolated from horse urine and on the alkali metal salts of three standard steroid conjugates. Spectra obtained in the different modes were of comparable intensity. Positive ion spectra were generally more complex due to the formation of alkali metal adduct ions containing several sodium cations. The most abundant ion in the negative ion spectra corresponded to the loss of the alkali metal cation to give [M]-. Thus, the structure of a conjugate can be defined from the combination of mass spectrometric techniques.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 96-99 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As part of a continuing research program associated with the detection of anabolic steroid residues in horse urine,1-8 normal samples from entire male horses have now been investigated. Isomers of three C-18 neutral steroids; 4-estron-17-ol-3-one (1), estrane-3,17-diol (2) and an unsaturated estranediol having a possible structure (3), have been identified in urine samples from two male horses aged 8 and 14 years. Of these three steroids, compound (2) was not detected in the urine of a 2.5 yr old entire male nor in the majority of post-race urine samples from entire male horses average age 3.8 yrs (n = 34). Ten of these samples showed tentative indications of this compound. Although the isolation of isomers of estrane-3,17-diol from human non-pregnancy urine has been reported previously,9 analysis of non-pregnancy urine samples in the present study did not reveal the presence of these compounds.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In steroid analysis in biological fluids, cleavage of conjugates is an essential step which can be achieved by either enzymatic or chemical hydrolysis. Where conjugation with both glucuronic acid and sulphate occurs, then the use of the enzyme preparation from Helix pomatia, containing both β-glucuronidase and aryl sulphatase activities, would appear to be advantageous. However, it has been shown that the sulphatase enzymes of Helix pomatia do not hydrolyse 17β-sulphates and that other enzymatic activities also present in the preparation can give rise to artefact formation with certain steroids.The artefacts produced from incubation of dehydroisoandrosterone with the enzyme preparation from Helix pomatia have been identified by gas chromatography/mass spectrometry (GC/MS) as androst-4-ene-3,17-dione, androsta-4,6-diene-3,17-dioue, androst-4-ene-3,6,17-trione and 6-hydroxyandrost-4-ene-3,17-dione. Incubation of androst-5-ene-3,17-diol produced a similar series of compounds with a 17-hydroxy function. Semi-quantitative GC/MS analysis has been used to determine the extent of these transformations in the presence of increasing amounts of the Helix pomatia preparation. Quantitative conversion in buffer can be obtained but the results from incubation in urine showed a marked modifying effect with minimal artefact formation. The enzyme preparation from Escherichia coli does not yield any artefacts and results are presented for the optimization of its use in the hydrolysis of the glucuronic acid conjugate of 5α-estrane-3β,17α-diol, the major metabolite of nandrolone in the horse.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 1030-1033 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Negative ion chemical mass spectra of some corticosteroids have been obtained by direct syringe introduction on to the Finnigan moving belt high-performance liquid chromatograph-mass spectrometer interface. Proprietaty preparations based upon dexamethasone, betamethasone and prednisolone were administered to horses at therapeutic dose level. Urine samples were extracted, the extracts purified by Sephadex LH-20 chromatography and the presence of the parent steroids in the eluates was confirmed by combined high-performance liquid chromatography negative ion chemical ionization mass spectrometry using ammonia as reagent gas.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vivo biotransformation of (1,2(n)-3H)1-dehydrotestosterone was studied in three equine male castrates and a number of neutral metabolites were identified in the urinary unconjugated and glucuronic acid conjugate fractions by gas chromatography/mass spectrometry. The metabolites were extracted from aliquots of the 0-24 h urine samples by Amberlite XAD-2 and separated into combined unconjugated plus glucuronic acid conjugated and sulphoconjugated fractions by Sephadex LH-20 column chromatography. After enzymatic hydrolysis of the glucuronides, the crude neutral unconjugated steroids plus the aglycones were partially purified by Kieselgel H chromatography and identified as their methyloxime trimethylsilyl derivatives. In the unconjugated fraction, the major metabolites were isomers of androsta-1,4-diene-6,16,17-triol-3-one. In the aglycone fraction a small amount of the parent steroid was present but the major metabolite was the 17α isomer androsta-1,4-dien-17α-ol-3-one. Other metabolites containing the 1,4-dien-3-one group were isomers of androsta-1,4-diene-16,17-diol-3-one and androsta-1,4-diene-6,16-diol-3-one. Reduction of the 4-ene functionality leading to the formation of 5-androst-1-en-16-ol-3,17-dione, 5-androst-1-ene-16,17-diol-3-one and of the 1-ene functionality leading to the formation of 5-androst-1-en-16-ol-3,17-dione, 5-androst-1-ene-16,17-diol-3-one and of the 1-ene functionality leading to the formation of testosterone and its further reduction leading to the formation of C19O2 and C19O3 androstane metabolites was observed. Some interesting features on the electron impact fragmentations of the methyloxime trimethlysilyl derivatives of steroids containing a 1,4-dien-3-one group were also observed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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