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Adaptations of skeletal muscle pyruvate dehydrogenase kinase in response to food-restriction in mitochondrial subpopulations

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dc.contributor.author MacPherson, Laura Lynn. en_US
dc.date.accessioned 2009-06-09T18:16:21Z
dc.date.available 2009-06-09T18:16:21Z
dc.date.issued 2007-06-09T18:16:21Z
dc.identifier.uri http://hdl.handle.net/10464/1557
dc.description.abstract University, 2006 Dr. Sandra J. Peters Pyruvate dehydrogenase (PDH) catalyses the decarboxylation of pyruvate, to form acetyl-CoA. PDH activity is down-regulated by intrinsic PDH kinases (predominantly PDK2 and PDK4 isoforms), but the understanding of the PDK isoform distribution and adaptation to nutritional stresses has been restricted to mixed mitochondrial populations, and not delineated between subsarcolemmal (SS) and intermyofibrillar (IMF) subpopulations. SS and IMF mitochondria exhibit distinct morphological and biochemical properties; however the functional differences are not well understood. This study investigated the effect of fed (FED) versus 48 h total foodrestriction (FR) on rat red gastrocnemius muscle PDK2 and 4 isoform content in SS and IMF mitochondria. PDK4 content was ~3-5 fold higher in SS mitochondria compared to IMF (p=0.001), and increased with FR -3-4- fold in both subpopulations (p<0.001). PDK2 was -2.5-4 fold higher in SS mitochondria compared to IMF (p=0.001), but PDK2 was unaltered with FR. Citrate synthase activity (|imol/min/mg mitochondrial protein) was not different between either subpopulation. As well there were no significant differences between mitochondrial subpopulations in PDH complex components in both fed and FR states. These results demonstrate that there is a markedly higher content of both PDK isofonns in SS compared to IMF mitochondria. Although PDK2 does not increase in either subpopulation in response to FR, PDK4 increases to a similar extent in both SS and IMF after 48 h food-restriction. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Muscles en_US
dc.subject Pyruvate kinase. en_US
dc.subject Mitochondria. en_US
dc.subject Nutrition. en_US
dc.title Adaptations of skeletal muscle pyruvate dehydrogenase kinase in response to food-restriction in mitochondrial subpopulations en_US
dc.type Electronic Thesis or Dissertation en_US
dc.degree.name M.Sc. Applied Health Sciences en_US
dc.degree.level Masters en_US
dc.contributor.department Applied Health Sciences Program en_US


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