Larsen S 2013 Abstract MiP2013
|Larsen S, Dohlmann TL, Hindsø M, Dela F, Helge JW (2013) High intensity training decreases mitochondrial ADP sensitivity in human adipose and skeletal muscle tissue. Mitochondr Physiol Network 18.08.|
It has previously been reported that mitochondrial ADP sensitivity decreases (higher Km’) with endurance training in human skeletal muscle . This decrease was accompanied by an increased maximal ADP stimulated mt-respiration (Jmax) and an increased maximal oxygen uptake (VO2max). It is not known whether high intensity training (HIT) has the same effect on mitochondria and if these changes also occur in mitochondria from human adipose tissue. The aim of this project was to investigate mitochondrial ADP sensitivity and maximal ADP stimulated respiration in human adipose and skeletal muscle tissue after six weeks of HIT. Twelve healthy overweight subjects (7 F/5 M) (age: 40±2 yrs, BMI: 32±2, VO2max: 2612±166 ml/min) were included in the study. The subjects underwent six weeks (3 times a week) of HIT. VO2max was measured pre and post training. Mitochondrial ADP sensitivity (Km’) and Jmax was measured pre and post HIT in adipose tissue and permeabilized muscle fibers by high-resolution respirometry (Oxygraph-2k, Oroboros, Insbruck, Austria). The adipose tissue was permeabilized with digitonin and the skeletal muscle fibers with saponin. The protocol used for respirometry was as follows: Malate (2 mM), Glutamate (10 mM) and ADP titrated in the following steps (0.05 – 0.10 – 0.25 – 0.50 – 1.00 – 2.50 – 5.00 mM). SigmaPlot was used to determine Km’ for ADP and Jmax.
VO2max was significantly improved after HIT. Mitochondrial ADP sensitivity was significantly (P<0.05) decreased after HIT in permeabilized skeletal muscle (0.14±0.02 mM vs. 0.29±0.03 mM), and the same trend was seen in adipose tissue although not significant (P=0.056; 0.11±0.02 mM vs. 0.16±0.04 mM). Jmax was similar after HIT in permeabilized skeletal muscle (21±1 pmol∙s-1∙mg-1 vs. 22±1 pmol∙s-1∙mg-1) as well as in adipose tissue (0.36±0.03 pmol∙s-1∙mg-1 vs. 0.36±0.03 pmol∙s1∙mg-1), before vs. after, respectively.
ADP sensitivity decreased in permeabilized human skeletal muscle and the same trend was seen in adipose tissue. This was accompanied by a similar maximal ADP stimulated respiration pre and post training in both skeletal muscle and adipose tissue. This is the first time that ADP sensitivity has been investigated in adipose tissue. Interestingly the HIT training adaptation in mitochondria from adipose tissue is similar to that observed in skeletal muscle although not with the same magnitude.
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Organism: Human Tissue;cell: Skeletal muscle, Fat Preparation: Intact organism, Permeabilized tissue
Regulation: ADP Coupling state: OXPHOS
Center for Healthy Aging, Dept of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. - Email: [email protected]
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