Effects of altitude, cold and heat on metabolic interrelationships in rats.

Adult male Wistar rats were exposed for 3 months either to simulated altitude or to hot or cold environments, and comparisons were made during the final month using body weight, food and water intake, the 24-hour fasting urine volume, and the excretion of sodium, potassium, phosphate, magnesium, calcium, urea, uric acid, creatinine, taurine, histidine, glycine, alanine, valine, aspartic acid, glutamic acid, methionine and serine. Correlational analyses showed that many of the above-listed variables remained in constant association in the different environments regardless of the extent of their separate quantitative changes. Intergroup changes in the variable-relationships noted in certain of these environments may indicate either an incomplete acclimatization or an environmentally specific adaptation.