Portland State University. Department of Biology
Date of Award
Master of Science (M.S.) in Biology
1 online resource (45 p.)
Rats -- Physiology, Temperature -- Physiological effect
Long-Evans rats were raised from birth to eight weeks of age at 5°C, 20°C and 30°C. Blood was taken from animals two to eight weeks of age and assayed for growth hormone and thyroid stimulating hormone. The 30°C reared rats were found to have the longest ear, tail and hind limbs, followed by the 20°C reared rats. The 5°C rats were found to have the shortest ear, tail and hind limb. The 30°C and 5°C reared rats were found to have similar masses at the termination of the experiment. The 20°C reared rats had the smallest mass. Differences in size between the three groups when compared on a weekly basis were not found to be related to weekly obtained serum levels of growth hormone and thyroid stimulating hormone. Food consumption was greatest for the 5°C reared rats followed by the 20°C reared rats. The 5°C reared rats were found to have the lowest routine metabolic rate in the 5°C chamber. The 20°C reared rats were found to have the lowest routine metabolic rate in both the 20°c and 30°C chamber.
When 30°C and 20°C reared rats were put in the 5°C chamber with the 5°C reared rats, they initially lost mass, however after three weeks in the 5°C chamber they began to gain mass. The 30°C reared rats gained mass at a greater rate than did the 20°C reared rats. The 5°C reared rats continued to gain mass throughout this period. While in the 5°C chamber the total food consumption of the 20°c reared rats was the greatest, whereas the 5°C and 30°C reared rats consumed similar amounts of food.
Quinn, Dana Elizabeth, "The effect of developmental temperature on morphology, energy metabolism, growth hormone and thyroid stimulating hormone in Long-Evans rats" (1978). Dissertations and Theses. Paper 2836.