REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY METHOD FOR THE ANALYSIS OF NITRO-ARGININE IN RAT PLASMA AND URINE

Nitro-L-arginine (L-NNA) is an inhibitor of the enzyme nitric oxide sy nthase (NOS). We developed a simple, sensitive and reproducible revers ed-phase high-performance liquid chromatographic method for detection of nitro-arginine (L- and D-enantiomer) in rat plasma and urine. Sampl es were treated with perchloric acid, neutralized and eluted through a C-8 reversed-phase column with a mobile phase of 18.5 mM heptanesulfo nic acid-10% methanol in water, using theophylline as an internal stan dard. Plasma recovery for both isomers was complete, and the sensitivi ty limit was 0.5 mu g/ml. This method may be used for disposition stud ies of L-NNA in small animals.