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Monaco 2018 Diabetologia

From Bioblast
Publications in the MiPMap
Monaco CMF, Proudfoot R, Miotto PM, Herbst EAF, MacPherson REK, Holloway GP (2018) α-linolenic acid supplementation prevents exercise-induced improvements in white adipose tissue mitochondrial bioenergetics and whole-body glucose homeostasis in obese Zucker rats. Diabetologia 61:433-44.

» PMID: 28965129

Monaco CMF, Proudfoot R, Miotto PM, Herbst EAF, MacPherson REK, Holloway GP (2018) Diabetologia

Abstract: While the underlying mechanisms in the development of insulin resistance remain inconclusive, metabolic dysfunction in both white adipose tissue (WAT) and skeletal muscle have been implicated in the process. Therefore, we investigated the independent and combined effects of α-linolenic acid (ALA) supplementation and exercise training on whole-body glucose homeostasis and mitochondrial bioenergetics within the WAT and skeletal muscle of obese Zucker rats.

We randomly assigned obese Zucker rats to receive a control diet alone or supplemented with ALA and to remain sedentary or undergo exercise training for 4 weeks (CON-Sed, ALA-Sed, CON-Ex and ALA-Ex groups). Whole-body glucose tolerance was determined in response to a glucose load. Mitochondrial content and bioenergetics were examined in skeletal muscle and epididymal WAT (eWAT). Insulin sensitivity and cellular stress were assessed by western blot.

Exercise training independently improved whole-body glucose tolerance as well as insulin-induced signalling in muscle and WAT. However, the consumption of ALA during exercise training prevented exercise-mediated improvements in whole-body glucose tolerance. ALA consumption did not influence exercise-induced adaptations within skeletal muscle, insulin sensitivity and mitochondrial bioenergetics. In contrast, within eWAT, ALA supplementation attenuated insulin signalling, decreased mitochondrial respiration and increased the fraction of electron leak to reactive oxygen species (ROS).

These findings indicate that, in an obese rodent model, consumption of ALA attenuates the favourable adaptive changes of exercise training within eWAT, which consequently impacts whole-body glucose homeostasis. The direct translation to humans, however, remains to be determined. Keywords: Exercise, Glucose homeostasis, Insulin signalling, Mitochondria, Obesity, PUFA, ROS, Respiration, Skeletal muscle, WAT Bioblast editor: Kandolf G O2k-Network Lab: CA Guelph Holloway GP

Labels: MiParea: Respiration, Exercise physiology;nutrition;life style, Pharmacology;toxicology  Pathology: Obesity 

Organism: Rat  Tissue;cell: Skeletal muscle, Fat  Preparation: Permeabilized tissue  Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase 

Pathway: F, N  HRR: Oxygraph-2k 

Labels, 2018-01