[Neutral peptide hydrolases in the blood serum and lungs in hypoxia]

In rats exposed to hypoxia (breathing 11% O2-N2 for 15 min), activity of neutral peptide hydrolases in lungs and serum was measured before and after altitude chamber training. When exposed to normal air breathing, activity of lung neutral peptide hydrolases was markedly higher in Group 1 rats, i.e. those in whom O2 consumption changed insignificantly in response to the hypoxic test, than in Group 2 rats, i.e. those in whom O2 consumption increased in response to the hypoxic test. After altitude chamber training activity of lung and serum neutral peptide hydrolases decreased in Group 1 rats and increased in Group 2 rats. The potential correlation between lung and blood neutral proteolysis is discussed. Its contribution to the biochemical control of oxygen transport via blood rheological properties and vascular tone is considered.