title: Improved method for simultaneous determination of L-arginine and its mono- and dimethylated metabolites in biological samples by high-performance liquid chromatography.
abstract: An improved method has been developed for the determination of L-arginine and its methylated metabolites, N(G)-monomethyl-L-arginine (L-NMMA), N(G),N(G)-dimethyl-L-arginine (asymmetric DMA, ADMA) and N(G),N(G)'-dimethyl-L-arginine (symmetric DMA, SDMA) in biological samples. Extraction of these compounds with a strong cation-exchange resin AG50W-X8 with L-homoarginine (2-amino-6-guanidinohexanoic acid) as an internal standard gave a recovery of more than 70% except for SDMA from plasma samples. After extracted samples were converted to fluorescent derivatives with o-phthalaldehyde (OPA) in an alkaline medium, the following high-performance liquid chromatographic separation with a ODS column (wide-pore size, 300 A) was successfully performed with an isocratic mobile phase system. The method permits quantitative determination of L-arginine and its methylated metabolites at concentrations as low as 4 microM and 0.18 microM, respectively. Using this method, the levels of L-arginine, L-NMMA, ADMA and SDMA in human plasma, urine and rat tissue were determined.
authors.affiliation: Graduate School Doctoral Program in Medical Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Pi
authors.forename: Y
authors.initials: Y
authors.lastname: Kumagai
authors.forename: G
authors.initials: G
authors.lastname: Sun
authors.forename: N
authors.initials: N
authors.lastname: Shimojo
mesh_terms: D000328:Adult; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D051381:Rats; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D001120:Arginine