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Stephenson 2013 Thesis Royal Melbourne Institute of Technology - Melbourne

From Bioblast
Publications in the MiPMap
Stephenson EJ (2013) Mitochondrial function in metabolic health. Thesis Royal Melbourne Institute of Technology - Melbourne: 106pp.

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Stephenson EJ (2013) Thesis Royal Melbourne Institute of Technology - Melbourne

Abstract: Inactivity-related diseases (such as obesity and insulin resistance) are a burden on Western society, with low cardiorespiratory fitness (maximal aerobic capacity, VO2max) a strong independent predictor of metabolic disease and all-cause mortality. The etiological basis of these disorders is polygenic and highly dependent on the environment (i.e., existing genes interact with environmental factors to result in phenotypic expression of these diseases). The work undertaken for this thesis comprised a series of independent but related studies aimed at enhancing our understanding of the relationship between genetic factors and environmental stimuli in determining the capacity for aerobic energy production in skeletal muscle and white adipose tissue (WAT). Rodent models of divergent intrinsic running capacity (and, by association, metabolic health profile) and environmental interventions (i.e., diet and exercise) were employed in order to explore some of the mechanisms that determine the capacity for mitochondrial energy production in these two insulin-responsive tissues. In the first investigation (Chapter 2), Long-Evans rats were given ad libitum access to either a Western Diet (WD; 40% energy (E) from fat, 17 % protein, and 43% carbohydrate (30% sucrose); n=12) or a control diet (CON; 16% E from fat, 21% protein, and 63% carbohydrate (10% sucrose); n=12) for 12 wk. Rats fed the WD consumed 23% more E than CON (P=0.0001), which was associated with greater increases in body mass (23%; P=0.0002) and adiposity (17%; P=0.03). There were no differences in fasting blood glucose concentration of glucose tolerance between diets, although fasting insulin was increased by 30% (P=0.007). Fasting serum triglycerides were also elevated in WD (86%; P=0.001). The maximal respiratory capacity of m. soleus (soleus) was greater following the WD (37%; P=0.02), as were the maximal activities of several mitochondrial enzymes (citrate synthase, CS; β-hydroxyacyl-CoA dehydrogenase, β-HAD; carnitine palmitoyltransferase). Protein expression of CS, uncoupling protein (UCP)-3, and individual respiratory complexes was greater after WD (all P<0.05) despite no differences in the expression of peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α) mRNA or protein....(AU)


Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 


Organism: Rat  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue  Enzyme: TCA cycle and matrix dehydrogenases 

Coupling state: LEAK, OXPHOS, ET  Pathway: N, S, NS, ROX  HRR: Oxygraph-2k