The effect of high altitude and caloric restriction on reactive carbonyl derivatives and activity of glutamine synthetase in rat brain.

Both exposure to high altitude (HA) and caloric restriction (CR) may influence free radical generation. The aim of the present study was to evaluate the effects of 4 wk chronic exposure to 4,000m of HA and CR (60% of CR of control (C) rats) on protein oxidation in brain. Eighteen rats with similar body mass were assigned to CR, HA and C rats. Reactive carbonyl derivatives (RCD), marker of protein oxidation, were measured by Western blot. In addition, the activity and protein content of glutamine synthetase (GS) were determined. The body mass of C rats was significantly higher (P< 0.001) than that of HA and CR groups. The quantified signal intensity of RCD was significantly stronger in C rats than in HA and CR rats. The activity of GS was significantly increased in CR rats, while the protein content of GS was decreased in HA rats compared to C group. The data suggest that both HA and CR decreases the accumulation of RCD in the brain, however the mechanism of the decrease seems to be different during HA and CR.