The conversion of arginine to nitric oxide (NO) is catalyzed by nitric oxide synthase (NOS), and asymmetric dimethylarginine (ADMA) is an inhibitor of that enzyme. When NO synthesis is blocked, a number of biochemical processes are immediately affected, including vasodilation, platelet aggregation, monocyte adhesion, and the inflammatory pathway. Current methods for quantitation of ADMA include immunoassays, where cross-reactivity is problematic, or mass spectrophotometric methods which require manual sample preparation including solid phase extraction and/or derivitization. We developed a simple, rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method to measure ADMA directly in EDTA plasma. |
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