McFarlane 2016 Thesis

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McFarlane SV (2016) Temperature-dependent alterations of brown adipose tissue metabolism during hibernation in the thirteen-lined ground squirrel, Ictidomys tridecemlineatus. Dissertation p74.

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McFarlane SV (2016) Dissertation

Abstract: 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.

Keywords: Uncoupled thermogenesis, Q10, electron transport system, Hibernation, Mitochondria, High resolution respirometry, Thirteen-lined ground squirrel

O2k-Network Lab: CA London Staples JF


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 

Stress:Temperature  Organism: Other mammals  Tissue;cell: Fat  Preparation: Intact cells, Isolated mitochondria  Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Uncoupling protein  Regulation: Temperature  Coupling state: LEAK, ROUTINE, OXPHOS, ET  Pathway: F, N  HRR: Oxygraph-2k 

2016-10