Observation on the reactions of the albino rat in simulated altitude.

Albino rats of the Wistar family were reared from the time of birth in a simulated altitude of about 6000 meters (barometric pressure 370 mm Hg) for a period of about 50 days. A number of these were killed after losing consciousness upon exposure to acute hypoxia. The others were killed without being first subjected to the acute hypoxia. Control groups of the same stock were reared for a corresponding period of time in a normal atmosphere at sea level and killed like the previous group. The animals reared in a simulated altitude displayed an increase in the 2,3-DPG content in the red blood cells, Hb concentration and the number of erythrocytes for one ml of blood. They are to be considered phenomena of adaptation, only slightly influenced by the acute hypoxia. The animals reared in a simulated altitude also displayed a displacement of the acid-base balance of the blood towards the acid side. This was even more accentuated in the group subjected to the acute hypoxia. It was observed, via the weight curve, that the animals reared in a simulated altitude presented a slower body growth in comparison to the control group. We were not able to demonstrate significant variations in the tolerance to acute hypoxia in the various groups studied.