Détail de la notice
Titre du Document
Uniaxial Cyclic Stretch Increases Glucose Uptake into C2C12 Myotubes through a Signaling Pathway Independent of Insulin-like Growth Factor I
Auteur(s)
Iwata M. ; Suzuki S. ; Hayakawa K. ; ...
Résumé
Insulin-like growth factor I (IGF-I), an autocrine/paracrine growth factor involved in myogenesis, has rapid effects on muscle metabolism. In a manner analogous to insulin and mechanical stimuli such as stretch, IGF-I stimulates glucose transport through recruitment of glucose transporters to surface membranes in skeletal muscles. It is known that IGF-I is secreted from skeletal muscle cells in response to stretch. Therefore, we examined whether IGF-I is involved in the mechanism by which mechanical stretch regulates glucose transport using cultured C2C12 myotubes. IGF-I increased 2-deoxy- D-glucose (2-DG) uptake, and this created an additive effect with mechanical stretch, suggesting that these stimuli enhance glucose transport through different mechanisms. In fact, IGF-I-stimulated 2-DG uptake was not blocked by dantrolene (an inhibitor of Ca 2+release from sarcoplasmic reticulum), whereas the stretch-stimulated effect was abolished. Conversely, the IGF-I-stimulated 2-DG uptake was prevented by phosphatidylinositol 3-kinase inhibitor wortmannin, which did not prevent the stretch-stimulated 2-DG uptake. In addition, experiments using media conditioned by stretched myotubes indicated that a mechanically induced release of locally acting autocrine/paracrine growth factors was not sufficient for induction of 2-DG uptake. Thus, our results demonstrate that mechanical stretch signaling for glucose transport is independent of the mechanism through which IGF-I increases this
Editeur
Thieme
Identifiant
ISSN : 1439-4286
Source
Hormone and metabolic research (Internet) A. 2009, vol. 41, n° 01, pp. 16-22 [7 pages]
Langue
Anglais
Copyright
Tous droits réservés © Georg Thieme Verlag Stuttgart, New York, 2009
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