Androgen metabolism in the dog

Yamamoto, Yukio; Osawa, Yosuke; Kirdani, Rashad Y.; Sandberg, A.A.

doi:10.1016/0022-4731(78)90194-2

Cited by 6 publications

(10 citation statements)

References 21 publications

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“…Previous studies have also indicated that sulphate conjugation is not a major pathway in the greyhound12, 13 and the major 16‐hydroxy metabolites observed in this study were all exclusively detected as glucuronides. The presence of 17‐epimeric metabolites in the glucuronide fraction has been observed to an extent in man and is believed to be partly due to enterohepatic circulation of metabolites,18 but this process has previously been reported as relatively minor in the dog despite significant biliary excretion 12…”

Section: Resultssupporting

confidence: 67%

“…However, epimerisation of 17α‐methyl steroids in man and horse has been shown to be associated with hydrolytic removal of sulphate conjugate groups, resulting in analytes being present in the free urinary fraction as well as in the glucuronide fraction 4, 18, 19. Previous studies have also indicated that sulphate conjugation is not a major pathway in the greyhound12, 13 and the major 16‐hydroxy metabolites observed in this study were all exclusively detected as glucuronides. The presence of 17‐epimeric metabolites in the glucuronide fraction has been observed to an extent in man and is believed to be partly due to enterohepatic circulation of metabolites,18 but this process has previously been reported as relatively minor in the dog despite significant biliary excretion 12…”

Section: Resultssupporting

confidence: 47%

“…An early study by Mosbach et al 11. into the faecal metabolism in the dog indicated that a large proportion of an oral dose was excreted by this route; an observation also supported by Yamamoto et al 12. Williams et al .…”

supporting

confidence: 52%

“…The metabolites that have been identified or tentatively identified are listed in Table 1. The sulphate fraction was not analysed as previous studies by the authors (unpublished data) and others12, 13 have indicated that sulphate conjugation does not appear to be a significant phase II metabolic pathway in the canine.…”

Section: Resultsmentioning

confidence: 99%

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Metabolism of methyltestosterone in the greyhound

Biddle

O’Donnell

Houghton

et al. 2009

Rapid Comm Mass Spectrometry

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Gas chromatography/mass spectrometry and selective derivatisation techniques have been used to identify urinary metabolites of methyltestosterone following oral administration to the greyhound. Several metabolites were identified including reduced, mono-, di- and trihydroxylated steroids. The major metabolites observed were 17alpha-methyl-5beta-androstane-3alpha-17beta-diol, 17alpha-methyl-5beta-androstane-3alpha,16alpha,17beta-triol, and a further compound tentatively identified as 17alpha-methyl-5z-androstane-6z,17beta-triol. The most abundant of these was the 17alpha-methyl-5beta-androstane-3alpha,16alpha,17beta-triol. This metabolite was identified by comparison with a reference standard synthesised using a Grignard procedure and characterised using trimethylsilyl (TMS) and acetonide-TMS derivatisation techniques. There did not appear to be any evidence for 16beta-hydroxylation as a phase I metabolic transformation in the greyhound. However, significant quantities of 16alpha-hydroxy metabolites were detected. Selective enzymatic hydrolysis procedures indicated that the major metabolites identified were excreted as glucuronic acid conjugates. Metabolic transformations observed in the greyhound have been compared with those of other mammalian species and are discussed here.

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Section: Resultssupporting

confidence: 67%

Section: Resultssupporting

confidence: 47%

supporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

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Metabolism of methyltestosterone in the greyhound

Biddle

O’Donnell

Houghton

et al. 2009

Rapid Comm Mass Spectrometry

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“…Selective enzymatic hydrolysis procedures indicated that the major metabolites were predominantly excreted as glucuronic acid conjugates and detection of the administration of norethisterone was possible for up to 8 days post‐dose using the methods described here. The sulphate fraction was not analysed as previous studies by the authors (unpublished data) and others have indicated that sulphate conjugation does not appear to be a significant phase II metabolic pathway in the canine.…”

Section: Resultsmentioning

confidence: 99%

Metabolism of norethisterone in the greyhound

Biddle

O’Donnell

Houghton

et al. 2013

Rapid Comm Mass Spectrometry

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The in vivo metabolism of Furazadrol in greyhounds

Pranata

Curtis

Waller

et al. 2021

Drug Testing and Analysis

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Samples of the ‘dietary supplement’ Furazadrol sourced through the internet have been reported to contain the designer anabolic androgenic steroids [1′,2′]isoxazolo[4′,5′:2,3]‐5α‐androstan‐17β‐ol (furazadrol F) and [1′,2′]isoxazolo[4′,3′:2,3]‐5α‐androstan‐17β‐ol (isofurazadrol IF). These steroids contain an isoxazole fused to the A‐ring and were designed to offer anabolic activity while evading detection, raising concerns over the potential for abuse of this preparation in sports. The metabolism of Furazadrol (F:IF, 10:1) was studied by in vivo methods in greyhounds. Urinary phase II Furazadrol metabolites were detected as glucuronides after a controlled administration. These phase II metabolites were subjected to enzymatic hydrolysis by Escherichia coli β‐glucuronidase to afford the corresponding phase I metabolites. Using a library of synthetically derived reference materials, the identities of seven urinary Furazadrol metabolites were confirmed. Major confirmed metabolites were isofurazadrol IF, 4α‐hydroxyfurazadrol 4α‐HF and 16α‐hydroxy oxidised furazadrol 16α‐HOF, whereas the minor confirmed metabolites were furazadrol F, 4β‐hydroxyfurazadrol 4β‐HF, 16β‐hydroxyfurazadrol 16β‐HF and 16β‐hydroxy oxidised furazadrol 16β‐HOF. One major hydroxyfurazadrol and two dihydroxyfurazadrol metabolites remained unidentified. Qualitative excretion profiles, limits of detection and extraction recoveries were established for furazadrol F and major confirmed metabolites. These investigations identify the key urinary metabolites of Furazadrol following oral administration, which can be incorporated into routine screening by anti‐doping laboratories to aid the regulation of greyhound racing.

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Androgen metabolism in the dog

Cited by 6 publications

References 21 publications

Metabolism of methyltestosterone in the greyhound

Metabolism of methyltestosterone in the greyhound

Metabolism of norethisterone in the greyhound

The in vivo metabolism of Furazadrol in greyhounds

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