Effects of somatotropin in rats acutely exposed to adverse environments

¹ Physiology-Biophysics Branch, School of Aviation Medicine, USAF Aerospace Medical Center, Brooks Air Force Base; and Psychiatric and Psychosomatic Research Laboratory, Veterans Administration Hospital; and Baylor University College of Medicine, Houston, Texas

Metabolic effects of acute (24-hr.) exposure to low barometric pressure (380 mm Hg), heat (35°C), or cold (2°C) were determined in fasting rats which had received subcutaneous injections of somatotropin (0.5 mg/100 gm b.wt.) 24 hours before and immediately before exposure. Comparison was made with rats exposed to the same conditions without pretreatment with somatotropin and with controls held under neutral conditions of temperature and pressure (24°C, 750 mm Hg). Somatotropin modified environmentally induced changes in 24-hour urinary excretion of urea, uric acid and phosphate and the urinary Na/K, Ca/P and uric acid/creatinine ratios. Suggestive evidence was thus obtained to support the hypothesis that somatotropin contributes to homeostasis.