Oxygen Transport, Utilization and Storage in Rats Acclimated to Altitude at Different Temperatures

¹ From the Department of Physiology and Biophysics, School of Aviation Medicine, USAF, Randolph Air Force Base, and the Clayton Foundation, Biochemical Institute, University of Texas, Austin, Texas

Oxygen transport, utilization and storage and related functions were studied in rats exposed to simulated altitude (18,000 ft.) at three different temperatures (5°, 24° and 36°C) for periods in excess of 3 months. Liver, heart, kidney and adrenal weights were altered only where thermal influences were involved. Adrenal weight in altitude-cold was greater than in cold alone. The oxygen transport function was normal in altitude-cold, but it was depressed in altitude-heat. Liver succinic dehydrogenase activity was elevated in all altitude groups, but more so in both the heat and cold. That of the adrenals was elevated most in the altitude-cold. Oxygen storage was unaffected by thermal factors.