Difference between revisions of "Larsen 2011 Acta Physiol (Oxf)"

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Larsen S, Kristensen JM, Stride N, Wojtaszewski JF, Helge JW, Dela F (2011) Skeletal muscle mitochondrial respiration in AMPKα2 kinase-dead mice. Acta Physiol (Oxf) Epub ahead of print.

» PMID:22192354

Larsen S, Kristensen JM, Stride N, Wojtaszewski JF, Helge JW, Dela F (2011) Acta Physiol (Oxf)

Abstract: AIM: To study whether the phenotypical characteristics (exercise intolerance; reduced spontaneous activity) of the AMPKα2 kinase-dead (KD) mice can be explained by a reduced mitochondrial respiratory flux rates (JO(2) ) in skeletal muscle. Secondly, the effect of the maturation process on JO(2) was studied.

METHODS: In tibialis anterior (almost exclusively type 2 fibres) muscle from young (12-17 weeks, n = 7) and mature (25-27 weeks, n = 12) KD and wild-type (WT) (12-17 weeks, n = 9; 25-27 weeks, n = 11) littermates, JO(2) was quantified in permeabilized fibres ex vivo by respirometry, using a substrate-uncoupler-inhibitor-titration (SUIT) protocol: malate, octanoyl carnitine, ADP and glutamate (GMO(3) ), + succinate (GMOS(3) ), + uncoupler (U) and inhibitor (rotenone) of complex I respiration. Citrate synthase (CS) activity was measured as an index of mitochondrial content.

RESULTS: Citrate synthase activity was highest in young WT animals and lower in KD animals compared with age-matched WT. JO(2) per mg tissue was lower (P < 0.05) in KD animals (state GMOS(3) ). No uncoupling effect was seen in any of the animals. Normalized oxygen flux (JO(2) /CS) revealed a uniform pattern across the SUIT protocol with no effect of KD. However, JO(2) /CS was higher [GMO(3) , GMOS(3) , U and rotenone (only WT)] in the mature compared with the young mice - irrespective of the genotype (P < 0.05).

CONCLUSION: Exercise intolerance and reduced activity level seen in KD mice may be explained by reduced JO(2) in the maximally coupled respiratory state. Furthermore, an enhancement of oxidative phosphorylation capacity per mitochondrion is seen with the maturation process. • Keywords: AMPKα2 kinase-dead (KD) mice; substrate-uncoupler-inhibitor-titration (SUIT) protocol

• O2k-Network Lab: DK_Copenhagen_Dela F

Labels:

Organism: Mouse Tissue;cell: Skeletal Muscle"Skeletal Muscle" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property. Preparation: Permeabilized Tissue"Permeabilized Tissue" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property. Enzyme: Complex I

HRR: Oxygraph-2k

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 {{Publication
 |title=Larsen S, Kristensen JM, Stride N, Wojtaszewski JF, Helge JW, Dela F (2011) Skeletal muscle mitochondrial respiration in AMPKα2 kinase-dead mice. Acta Physiol (Oxf) Epub ahead of print.
 |info=[http://www.ncbi.nlm.nih.gov/pubmed/22192354 PMID:22192354]
 |authors=Larsen S, Kristensen JM, Stride N, Wojtaszewski JF, Helge JW, Dela F
@@ Line 13: / Line 13: @@
 CONCLUSION: Exercise intolerance and reduced activity level seen in KD mice may be explained by reduced JO(2) in the maximally coupled respiratory state. Furthermore, an enhancement of oxidative phosphorylation capacity per mitochondrion is seen with the maturation process.
 |keywords=AMPKα2 kinase-dead (KD) mice; substrate-uncoupler-inhibitor-titration (SUIT) protocol
+|mipnetlab=DK_Copenhagen_Dela F
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+|kinetics=Inhibitor; Uncoupler
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