Induction of mouse liver glyoxalase I by hypobaric hypoxia.

Hypobaric hypoxia at 0.45 atm induced a reversible increase of mouse liver glyoxalase I. The levels of this enzyme increased after an exposure of 20 h and 20 + 20 h, whereas the activity decreased to the control values after 20 h at room pressure. Before the treatment, some animals received tritiated leucine (i.p.). Glyoxalase I was purified to homogeneity. The pure enzyme from the treated animals showed 20-times more radioactivity than the controls. Thus, the increase in specific activity is due to new protein synthesized in response to the treatment at 0.45 atm. The activities of glyoxalase II and glutathione S-transferase were not affected by the treatment.