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.
| Identifer | oai:union.ndltd.org:pdx.edu/oai:pdxscholar.library.pdx.edu:open_access_etds-3841 |
| Date | 01 January 1978 |
| Creators | Quinn, Dana Elizabeth |
| Publisher | PDXScholar |
| Source Sets | Portland State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Dissertations and Theses |
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