A stereochemical examination of the equine metabolism of 17alpha-methyltestosterone.
An investigation was conducted into the stereochemistry of the equine urinary metabolites of 17alpha-methyltestosterone observed after oral administration. Standards of the complete range of C3/C5/C16 stereoisomeric 17alpha-methylandrostane-3,17beta-diols, 17alpha-methylandrostane-3,16,17beta-triols and 17alpha-hydroxymethylandrostane-3,17beta-diols were purchased or synthesised, and were used to unequivocally identify the absolute structures of the metabolites. Phase I metabolism was found to involve combinations of Delta(4)-3-ketone reduction with both 5alpha,3beta- and 5beta,3alpha-stereochemistry, hydroxylation at C16 with both 16alpha- and 16beta-stereochemistry and hydroxylation of the 17alpha-methyl substituent. Phase II metabolism involved mainly sulfation with a lesser degree of beta-glucuronidation.
McKinney
Andrew R
AR
Australian Racing Forensic Laboratory, Kensington, NSW, Australia. amckinney@racingnsw.com.au <amckinney@racingnsw.com.au>
Suann
Craig J
CJ
Stenhouse
Allen M
AM
D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry; D006736:Horses; D008777:Methyltestosterone / Q000378:metabolism* / Q000652:urine; D013237:Stereoisomerism
D008777:Methyltestosterone