Urinary metabolites of 2-bromoethanamine identified by stable isotope labelling: evidence for carbamoylation and glutathione conjugation.
2-Bromoethanamine (BEA) causes renal papillary necrosis (RPN) in rats after a single dose and has been widely used as a model compound for studying the lesion. Although the metabolism of BEA may be an important determinant of toxicity, the metabolic fate of the compound has not been fully elucidated. To date, the only identified BEA metabolites are aziridine, 2-oxazolidone and 5-hydroxy-2-oxazolidone. In this study, stable isotope labelling (SIL) of BEA analogs ((¹³C and ²H) were used to differentiate generated BEA metabolites from endogenous molecules which enabled the accurate liquid chromatography mass spectrometry detection of more than 180 novel metabolites. BEA metabolism was evaluated in rats after acute administration of a non-toxic dose (50 mg/kg) and a toxic dose (250 mg/kg) that caused frank RPN and polyuria. Newly identified metabolites include three carbamoylation products, two mercapturic acids and a group of amino acid conjugates. Overall, the results indicate that BEA metabolism is very complex, suggest the potential formation of reactive intermediates and establish that BEA is subject to conjugation with glutathione. The results also demonstrate the utility and sensitivity of the SIL approach for identification of metabolites from small, reactive compounds.
Bristol-Myers Squibb, Princeton, NJ 08543, USA. petia.shipkova@bms.com
Petia
P
Shipkova
Jeffrey D
JD
Vassallo
Nelly
N
Aranibar
Serhiy
S
Hnatyshyn
Haiying
H
Zhang
T Andrew
TA
Clayton
Glenn H
GH
Cantor
Mark
M
Sanders
Muireann
M
Coen
John C
JC
Lindon
Elaine
E
Holmes
Jeremy K
JK
Nicholson
Lois
L
Lehman-McKeeman
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002219:Carbamates / Q000378:metabolism*; D005021:Ethylamines / Q000737:chemistry / Q000633:toxicity / Q000652:urine*; D005978:Glutathione / Q000378:metabolism*; D007553:Isotope Labeling / Q000379:methods*; D007668:Kidney / Q000187:drug effects / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000596:Amino Acids; D002219:Carbamates; D005021:Ethylamines; C004504:2-bromoethylamine; D005978:Glutathione