Stephenson 2012 Am J Physiol Endocrinol Metab
Stephenson EJ, Camera DM, Jenkins TA, Lee JS, Kosari S, Hawley JA, Stepto NK (2012) Skeletal muscle respiratory capacity is enhanced in rats consuming an obesogenic Western diet. Am J Physiol Endocrinol Metab [Epub ahead of print]. |
Stephenson EJ, Camera DM, Jenkins TA, Lee JS, Kosari S, Hawley JA, Stepto NK (2012) Am J Physiol Endocrinol Metab
Abstract: Obesity-induced lipid oversupply promotes skeletal muscle mitochondrial biogenesis. Previous investigations have utilized extreme high-fat diets (HFD) to induce such mitochondrial perturbations despite their disparity from human obesogenic diets. Here, we evaluate the effects of Western diet (WD)-induced obesity on skeletal muscle mitochondrial function. Long-Evans rats were given ad libitum access to either a WD (40% energy (E) from fat, 17% protein and 43% carbohydrate (30% sucrose), n=12) or a control diet (CON, 16% of E from fat, 21% protein and 63% carbohydrate, 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 or glucose tolerance between diets, although fasting insulin was increased by 40% (P=0.007). Fasting serum triglycerides were also elevated in WD (86%, P=0.001). The maximal capacity of the electron transfer system was greater following WD (37%; P=0.02), as were the maximal activities of several mitochondrial enzymes (citrate synthase, Ξ²-hydroxyacyl-CoA dehydrogenase, carnitine palmitoyl-transferase). Protein expression of citrate synthase, UCP3 and individual respiratory complexes were greater after WD (P<0.05) despite no differences in the expression of peroxisome proliferator-activated receptors (PPAR)Ξ±, PPAR-Ξ΄, or PPAR-Ξ³ coactivator (PGC)-1 mRNA or protein abundance. We conclude that the respiratory capacity of skeletal muscle is enhanced in response to the excess energy supplied by a WD. This is likely due to an increase in mitochondrial density, which at least in the short term, and in the absence of increased energy demand, may protect the tissue from lipid-induced impairments in glycemic control. β’ Keywords: Western diet (WD)-induced obesity
β’ O2k-Network Lab: AU Melbourne Stepto NK
Labels:
Organism: Rat
Tissue;cell: Skeletal muscle
Regulation: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
HRR: Oxygraph-2k