The role of L-arginine/L-homoarginine/nitric oxide pathway for aortic distensibility and intima-media thickness in stroke patients.

Asymmetric dimethylarginine (ADMA) and L-homoarginine (hArg) are L-arginine (Arg) metabolites derived from different pathways. Protein arginine N-methyltransferase (PRMT) and subsequent proteolysis of proteins containing methylarginine residues release ADMA. Arginine:glycine amidinotransferase (AGAT) converts Arg to hArg and guanidinoacetate (GAA).

Simultaneous GC-ECNICI-MS measurement of nitrite, nitrate and creatinine in human urine and plasma in clinical settings.

Creatinine in urine is a useful biochemical parameter to correct the urinary excretion rate of endogenous and exogenous substances. Nitrite (ONO) and nitrate (ONO) are metabolites of nitric oxide (NO), a signalling molecule with multiple biological functions. Under certain and standardized conditions, the concentration of nitrate in the urine is a suitable measure of whole body NO synthesis.

Simultaneous stable-isotope dilution GC-MS measurement of homoarginine, guanidinoacetate and their common precursor arginine in plasma and their interrelationships in healthy and diseased humans.

Low concentrations of L-homoarginine (hArg) in plasma or serum and urine have recently emerged as a novel cardiovascular risk factor. Previously, we reported gas chromatography-mass spectrometry (GC-MS) and GC-tandem MS (GC-MS/MS) methods for the quantitative determination of hArg and Arg in plasma, serum, urine and other biological samples. In these methods, plasma and serum are ultrafiltered by means of commercially available cartridges (10 kDa), and 10-µL ultrafiltrate aliquots are subjected to a two-step derivatization procedure, yielding the methyl ester tri(N-pentafluoropropionyl) derivatives.