Acute Exercise Improves Insulin Clearance and Increases the Expression of Insulin-Degrading Enzyme in the Liver and Skeletal Muscle of Swiss Mice

PLoS One. 2016 Jul 28;11(7):e0160239. doi: 10.1371/journal.pone.0160239. eCollection 2016.

Abstract

The effects of exercise on insulin clearance and IDE expression are not yet fully elucidated. Here, we have explored the effect of acute exercise on insulin clearance and IDE expression in lean mice. Male Swiss mice were subjected to a single bout of exercise on a speed/angle controlled treadmill for 3-h at approximately 60-70% of maximum oxygen consumption. As expected, acute exercise reduced glycemia and insulinemia, and increased insulin tolerance. The activity of AMPK-ACC, but not of IR-Akt, pathway was increased in the liver and skeletal muscle of trained mice. In an apparent contrast to the reduced insulinemia, glucose-stimulated insulin secretion was increased in isolated islets of these mice. However, insulin clearance was increased after acute exercise and was accompanied by increased expression of the insulin-degrading enzyme (IDE), in the liver and skeletal muscle. Finally, C2C12, but not HEPG2 cells, incubated at different concentrations of 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) for 3-h, showed increased expression of IDE. In conclusion, acute exercise increases insulin clearance, probably due to an augmentation of IDE expression in the liver and skeletal muscle. The elevated IDE expression, in the skeletal muscle, seems to be mediated by activation of AMPK-ACC pathway, in response to exercise. We believe that the increase in the IDE expression, comprise a safety measure to maintain glycemia at or close to physiological levels, turning physical exercise more effective and safe.

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Animals
  • Cell Line
  • Enzyme Activation
  • Hep G2 Cells
  • Humans
  • Hydrolysis
  • Insulin / metabolism*
  • Insulysin
  • Islets of Langerhans / metabolism
  • Liver / enzymology*
  • Male
  • Mice
  • Muscle, Skeletal / enzymology*
  • Oxygen Consumption
  • Physical Conditioning, Animal*

Substances

  • Insulin
  • AMP-Activated Protein Kinases
  • Insulysin

Grants and funding

This work was supported by the Fundação de Amparo e Pesquisa do Estado de São Paulo (FAPESP, http://www.fapesp.br/, grant numbers 2013/07607-8 and 2014/24719-7) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, http://cnpq.br/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.