RT Journal Article
SR Electronic
T1 SPECIES DIFFERENCES IN METABOLISM AND PHARMACOKINETICS OF A SPHINGOSINE-1-PHOSPHATE RECEPTOR AGONIST IN RATS AND DOGS: FORMATION OF A UNIQUE GLUTATHIONE ADDUCT IN THE RAT
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1367
OP 1375
DO 10.1124/dmd.105.009027
VO 34
IS 8
A1 M. Reza Anari
A1 Mellissa D. Creighton
A1 Jason S. Ngui
A1 Richard A. Tschirret-Guth
A1 Yohannes Teffera
A1 George A. Doss
A1 Wei Tang
A1 Nathan X. Yu
A1 Suzanne L. Ciccotto
A1 Donald F. Hobra, Jr.
A1 John B. Coleman
A1 Stella H. Vincent
A1 David C. Evans
YR 2006
UL http://dmd.aspetjournals.org/content/34/8/1367.abstract
AB The pharmacokinetics and metabolism of 1-(4-((4-phenyl-5-trifluoromethyl-2-thienyl)methoxy)benzyl)azetidine-3-carboxylic acid (MRL-A), a selective agonist for the sphingosine-1-phosphate 1 (S1P1) receptor, were investigated in rats and dogs. In both species, more than 50% of the dose was excreted in bile. Specific to the rat, and observed in bile, were a taurine conjugate of MRL-A and a glucuronide conjugate of an azetidine lactam metabolite. In dogs, a smaller portion of the dose (54% of administered dose) was excreted intact in bile, and the major metabolites detected were an azetidine N-oxide of MRL-A and an acylglucuronide of an N-dealkylation product. This latter metabolite was also observed in rat bile. Stereoselective formation of the N-oxide isomer was observed in dogs, whereas the rat produced comparable amounts of both isomers. The formation of a unique glutathione adduct was observed in rat bile, which was proposed to occur via N-dealkylation, followed by reduction of the putative aldehyde product to form the alcohol, and dehydration of the alcohol to generate a reactive quinone methide intermediate. Incubation of a synthetic standard of this alcohol in rat microsomes fortified with reduced glutathione or rat hepatocytes resulted in formation of this unique glutathione adduct. The American Society for Pharmacology and Experimental Therapeutics