Temperature-dependent alterations of brown adipose tissue metabolism during hibernation in the thirteen-lined ground squirrel, <i>Ictidomys tridecemlineatus</i>.

Brown adipose tissue (BAT) is the major thermogenic tissue in small eutherian mammals. In hibernators, seasonal modifications of BAT are well documented but little is known about its functional regulation during hibernation. BAT metabolism is activated by sympathetic stimulation, so I hypothesized that further regulation at the mitochondrial level, as seen in other hibernator tissues, would be of little advantage. Contrary to my predictions, respiration rates of BAT mitochondria isolated from torpid thirteen-lined ground squirrels were suppressed by up to 62% compared with rates from individuals that aroused to interbout euthermia (IBE), when measured at 37°C. At 10°C, however, these rates did not differ between torpor and IBE. Contrary to these results, activities of electron transport system enzymes and brown adipocyte respiration did not differ between torpor and IBE, regardless of assay temperature. The data suggest that BAT mitochondria become less temperature sensitive during torpor, allowing sustained function at low body temperatures.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Biology

Grantor dc:publisher

The University of Western Ontario

Year dc:date.issued

2016

Author dc:creator

• McFarlane, Sarah V

Advisor dc:contributor.advisor

• James F. Staples

• uncoupled thermogenesis
• Q10
• electron transport system
• hibernation
• mitochondria
• high resolution respirometry
• thirteen-lined ground squirrel

Language dc:language.iso

en_ca

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/33910

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/33910