Is S-nitroso-N-acetyl-L-cysteine a circulating or an excretory metabolite of nitric oxide (NO) in man? Assessment by gas chromatography-mass spectrometry.
S-Nitroso-L-cysteine has been shown to be a circulating metabolite of the L-arginine-derived nitric oxide (NO.) in mammals. We describe here a highly sensitive gas chromatographic-mass spectrometric (GC-MS) method for the measurement of S-nitroso-N-acetyl-L-cysteine, the potential mercapturic acid of S-nitroso-L-cysteine, in human plasma and urine. For use as internal standard (I.S.) in this method we synthesized S-[15N]nitroso-N-[2H3]acetyl-L-cysteine. In plasma (n = 10) and urine (n = 30) samples of healthy humans no S-nitroso-N-acetyl-L-cysteine was detected (detection limit approximately 1 nM). Injecting the I.S. in the rat showed a good recovery of the I.S. but no endogenous S-nitroso-N-acetyl-L-cysteine. Our results suggest that renal N-acetylation of S-nitroso-L-cysteine does not represent a metabolic pathway in man.
Tsikas
D
D
Institute of Clinical Pharmacology, Hannover Medical School, Germany.
Rossa
S
S
Stichtenoth
D O
DO
Raida
M
M
Gutzki
F M
FM
Frölich
J C
JC
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003545:Cysteine / Q000031:analogs & derivatives* / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D008322:Mammals; D009569:Nitric Oxide / Q000378:metabolism*; D009587:Nitrogen Isotopes; D051381:Rats; D012015:Reference Standards; D012016:Reference Values; D026403:S-Nitrosothiols; D012680:Sensitivity and Specificity; D014316:Tritium
D007202:Indicators and Reagents; D009587:Nitrogen Isotopes; D026403:S-Nitrosothiols; D014316:Tritium; D009569:Nitric Oxide; C021315:S-nitrosocysteine; D003545:Cysteine