Skeletal muscle mitochondria as a source of non-shivering thermogenesis in the marsupial Anthechinus flavipes

Jastroch, Martin and Withers, Kerry and Klingenspor, Martin (2005) Skeletal muscle mitochondria as a source of non-shivering thermogenesis in the marsupial Anthechinus flavipes. In: 22nd Annual Conference of the Australian and New Zealand Society for Comparative Physiology and Biochemistry (ANZSCPB 2005), 09-11 Dec 2005, Dunedin, New Zealand.


The source of non-shivering thermogenesis (NST) in non-placental mammals is not known as they apparently lack
brown adipose tissue (BAT) and uncoupling protein 1 (UCP1). In placental mammals, UCP1 mediates uncoupled
respiration in BAT to generate heat. A thermogenic role of UCP3 and the adenine nucleotide transporter (ANT)
has been debated for bird skeletal muscle. It has been established that 4-hydroxy-2-trans-nonenal (HNE) induces
uncoupling activity by UCPs and/or ANT. Whether UCP or ANT is activated can be distinguished by GDPinhibition
of UCPs or carboxyatractyloside (CAT)-inhibition of the ANT. Here, we investigate the role of proton
conductance, UCP3 and ANT in skeletal muscle mitochondria during cold exposure of marsupials. We acclimated
the yellow-footed Antechinus (A. flavipes) to either 10° C or 24°C for 3-4 weeks and measured proton leakage in
isolated skeletal muscle mitochondria. Whereas basal proton conductance was unchanged between different
acclimation temperatures, a higher inducible proton conductance by HNE was observed in the cold acclimated
group. Inhibition by CAT indicated uncoupling activity by the ANT. Pertaining to UCP3, GDP-inhibition could
not be observed and might have been missed by applying assay conditions routinely used for rodents. Regarding
the dominant contribution of skeletal muscle to body mass, we demonstrate a potential role of their mitochondria
in adaptive thermogenesis. The capacity of proton leakage is increased in the cold and can be regulated by an ANTdependent mechanism. The present study provides no evidence for the involvement of UCP3 in adaptive
thermogenesis of marsupials.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: Abstract 80. Conference publication consists of only the abstracts of papers presented at the conference.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 00:29
Last Modified: 27 Jan 2012 04:36
Uncontrolled Keywords: non-shivering thermogenesis; marsupials
Fields of Research : 07 Agricultural and Veterinary Sciences > 0707 Veterinary Sciences > 070702 Veterinary Anatomy and Physiology

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