[The compensatory-adaptive mechanisms in nitrite-induced hypoxia in rats].

Concentration of blood proteins, alpha-amino nitrogen, cGMP and endothelin-1,2 was studied in rat's blood at nitric hypoxia. The injection of NaNO2 (5 mg/100 g body weight) was followed by decrease in total protein, albumin and hemoglobin content and by sharp increase in methemoglobin and Hb-NO complexes concentration in rat's blood. Simultaneously, the elevation of free amino acids and peptides with m.w. 2500 D in blood was discovered. One of these peptides was the endothelin-1,2, whose concentration increased twice in plasma at nitric hypoxia. The increase in endothelin and cGMP concentrations is mostly linked with activation of compensative mechanisms, arising as a response to high concentrations of nitro compounds and NO in rats.