Stable isotope-labeled tryptophan as a precursor for studying the disposition of quinolinic acid in rabbits.
The utility of stable isotope-labeled tryptophan as a precursor for studying the disposition of quinolinic acid was investigated. TRP-D5 at doses of 50, 25 or 10 mg/kg was administered to rabbits. Blood and CSF samples were taken for up to 6 hours. There was no loss of deuterium from the tryptophan and the specifically tri-deuterated quinolinic acid measured in plasma and CSF. CSF levels of QUIN-D3 remained elevated 6 hours following TRP-D5 administration. Further studies of the CNS disposition of quinolinic acid and other metabolites of the kynurenine pathway employing stable isotope-labeled tryptophan as precursor at appropriate doses and with extended sampling are in progress.
Boni
R L
RL
Laboratory of Clinical Science, NIMH, Bethesda, Maryland 20892.
Heyes
M P
MP
Bacher
J D
JD
Yergey
J A
JA
Ji
X D
XD
Abramson
F P
FP
Markey
S P
SP
D000818:Animals; D003903:Deuterium; D006207:Half-Life; D007737:Kynurenine / Q000378:metabolism; D008297:Male; D017378:Quinolinic Acid; D011805:Quinolinic Acids / Q000032:analysis*; D011817:Rabbits; D014018:Tissue Distribution; D014364:Tryptophan / Q000378:metabolism / Q000493:pharmacokinetics*
D011805:Quinolinic Acids; D007737:Kynurenine; D014364:Tryptophan; D003903:Deuterium; D017378:Quinolinic Acid