EN
Three classical direct nitric oxide (NO) donors, 3-morpholine-sydnonimine (SIN-1), S-nitroso-N-acetyl-d, 1-penicillamine (SNAP) and sodium nitroprusside (NaNP) as well as two indirect NO donors, molsidomine (MSL) and glyceryl trinitrate (GTN) were studied for their potencies to generate superoxide anions,to scavenge superoxide anions, to consume molecular oxygen and to inhibit <lipid oxidation>. Out of five NO donors only those which were spontaneous releasers of NO at physiological pH were also scavengers of superoxidase anions which has been generated by xanthine: xanthine oxidase system (SIN-1 IC50 19 ?M, SNAP IC50 416 ?M) and inhibitors of the Fe3+ and ascorbate stimulated oxidation of rat liver lipids (SIN-1 IC50 76 ?M, SNAP IC50 12 ?M). Only SIN-1 at high concentrations of 300-5000 yM generated superoxidase anions as detected by a SOD inhibitable reduction of nitroblue tetrazolium. None of the in vitro studied activities were exerted by NaNP, MLS and GTN.