Nitrogen and Electrolyte Excretion of Rats Chronically Exposed to Adverse Environments

¹ From the Biochemical Institute, University of Texas, Austin, and the School of Aviation Medicine, U.S. Air Force, Randolph Air Force Base, Texas

Urinary excretion patterns of adult male Wistar rats exposed for 11 weeks to control (25°C) or to adverse conditions (5°C, 35°C), or simulated altitude (equivalent to 18,000 ft.) were determined using 24-hour fasting urine specimens collected weekly during the final 4 weeks. Relative to metabolic body weight (kg^3/4), fasting water intake tended to vary directly with temperature, but urinary sodium, potassium, magnesium, calcium, phosphate, urea, valine and alanine tended to vary inversely with temperature. Creatinine, uric acid, histidine, glycine, serine, methionine, glutamic acid and aspartic acid excretion tended to vary nonlinearly with temperature. Altitude induced reductions in the majority of the urinary constituents.