Record Details
Field | Value |
---|---|
Title | Glycogen utilization in newborn rats subjected to cold stress |
Names |
Van Tassel, Loren Eugene
(creator) Hisaw, Frederick L. (advisor) |
Date Issued | 1965-05-07 (iso8601) |
Note | Graduation date: 1965 |
Abstract | Newborn rats exhibit a torporous response to cold stress at 2°C from which they revive after several hours exposure even though respiratory, cardiovascular, and muscular movements have ceased. At less severe temperatures (20 to 25°C) the rats respond with a non-torporous decrease in metabolic and physiologic activity and a lowering of body temperature to that of the environment. This experiment was an attempt to determine if anaerobic glycolysis contributed to the energy required during the period of anoxic torpor at 2°C, as well as the role of glycogen at 22°C. Control animals were kept at 32°C (nest temperature). After newborn rats had been exposed to one of the three experimental temperatures (2, 22, or 32°C) for a specified time interval up to ten hours, they were killed by quick-freezing. Samples of liver and muscle tissue were analyzed for glycogen concentration or for lactic acid. Survival time at 2 to 6°C was indicated in a separate group of animals by signs of life during rewarming: It was found that glycogen was depleted to a greater extent during cold exposure than at nest temperature. This indicates that the effects of cold inhibited those factors maintaining glycogen more than those factors utilizing it. The degree of lactic acid increase at 2°C indicated anaerobic glycolysis, while more complete oxidation of glycolytic intermediates was suggested at 22°C. Older animals were found to have a significantly higher liver glycogen concentration than younger ones, yet they succumbed to cold more readily than did the younger rats. This indicates that maturation affected resistance to cold more than did glycogen concentration. |
Genre | Thesis/Dissertation |
Topic | Cold -- Physiological effect |
Identifier | http://hdl.handle.net/1957/48084 |