[Inhibition of the antioxidative activity of plasma by sodium azide]

Powerful antioxidant activity of human plasma was demonstrated by measuring the thiobarbituric acid reaction and Fe+2-induced chemiluminescence. Inhibition of lipid peroxidation was shown both for plasma lipids and for the suspension of egg lipoproteins, which was taken as a model system. The inhibitory effect of plasma peroxidation was removed by azide Na taken in the concentration of 0.5 mg/ml, but caeroplasmin activity in the plasma was completely suppressed at NaN3 concentration equal to 0.1 mg/ml. A low correlation (r = 0.75) between caeruloplasmin activity in the blood plasma and extent of chemiluminescence activation obtained in the presence of NaN3 was found. The presented data led to an assumption that only a part of lipid peroxidation inhibitors in the plasma can be attributed with caeruloplasmin.