FRANK, C. L.*; CAREY, H. V.; Fordham Univ.; Univ. of Wisconsin: The physiological stress induced by mammlian torpor

Mammalian torpor is enhanced by a high polyunsaturated fatty acid (PUFA) diet, consequently the tissues of hibernating mammals tend to have high PUFA contents. Lipid peroxidation is a chain reaction initiated between reactive oxygen species (ROS) and PUFAs, producing lipid peroxides that are toxic to cells. We thus predicted that lipid peroxidation increases during mammalian torpor. Laboratory experiments were conducted with two species of ground squirrels, Spermophilus lateralis and S. tridecemlineatus , to test this prediction. Rates of lipid peroxidation in white adipose tissue (WAT), brown adipose tissue (BAT), and small intestinal mucosa were determined during different physiological states by measuring conjugated diene (CD) levels. Both WAT and BAT had higher CD contents in summer vs. hibernating squirrels, but CD levels during hibernation were greater than those observed just after spring emergence. Conjugated diene content of intestinal mucosa was greater during hibernation than during the summer feeding period. Significant tissue damage through lipid peroxidation may therefore be associated with torpor.