Insulin resistance and obesity are associated with a reduction of mitochondrial content in various tissues of mammals. Moreover, a reduced nitric oxide (NO) bioavailability impairs several cellular functions including mitochondrial biogenesis and insulin-stimulated glucose uptake, two important mechanisms of body adaptation in response to physical exercise. Although these mechanisms have been thoroughly investigated in skeletal muscle and heart, few studies have focused on the effects of exercise on mitochondria and glucose metabolism in adipose tissue.
In this study we compared the in vivo effects of chronic exercise in subcutaneous adipose tissue of wild type (WT) and eNOS knockout (eNOS-/-) mice after a swim training period. Then we investigated the in vitro effects of NO on mouse 3T3-L1 and human subcutaneous adipose tissue-derived adipocytes, after a chronic treatment with a NO donor (DETA-NO).
We observed that swim training increases mitochondrial biogenesis, mitochondrial DNA (mtDNA) content and glucose uptake in subcutaneous adipose tissue of WT but not eNOS-/- mice. Furthermore we observed that DETA-NO promotes mitochondrial biogenesis and elongation, glucose uptake and GLUT4 translocation in cultured murine and human adipocytes. These results point to the crucial role of the eNOS-derived NO in the metabolic adaptation of subcutaneous adipose tissue to exercise training.
* Dr. Quarta is currently affiliated with the Dept. of Nephrology and Neurological Sciences, School of Medicine, Stanford University, USA.
R.V. and E.N. contributed equally to this work
- Received August 12, 2013.
- Accepted March 8, 2014.
- © 2014 by the American Diabetes Association.
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