[Chemiluminescent analysis and some indicators of nitrogen catabolism in rat blood plasma in hypoxia with subsequent hyperoxia].

Different regimens of oxygenation were studied in rats: acute hypoxia (9,000 m, 3 hrs), acute hyperoxia (0.7 MPa O2), which caused convulsions, and their simultaneous effects. Under these conditions the following parameters were evaluated: the rate of Fe(2+)-induced chemiluminescence, content of nitrogen and peptide catabolism products (urea, urates and middle molecule peptides) as well as total peroxidase activity, content of extraerythrocyte hemoglobin and lactic acid in blood plasma. Distinct inhibition of the chemiluminescence rate was found in all the three experimental groups studied; accumulation of uric acid, middle mass peptides, extraerythrocyte hemoglobin, lactic acid as well as an increase in the total peroxidase activity were observed in hyperoxia and in simultaneous effect of hypo- and hyperoxia; total peroxidase activity was decreased in rats with acute hypoxia. Accumulation of urates and middle mass peptides was considered according to these substances capacity to inhibit free radical oxidation in vivo.