Journal
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Volume 331, Issue 4, Pages 1317-1323Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2005.04.048
Keywords
HSP72; calcineurin; thyroid hormone; myosin heavy chain; plantaris
Categories
Ask authors/readers for more resources
The content of both heat shock protein 72 (HSP72) and calcineurin (CaN) in skeletal muscle fibers have been reported to be associated with the slow phenotype. The purpose of the present study was to determine the adaptations/contributions of HSP72 and CaN to experimental conditions producing dramatic shifts in fiber phenotype. Two weeks of functional overload (FO) of the rat plantaris by cutting tie tendons of its major synergists resulted in a shift towards a slower MHC profile. Two weeks of thyroid hormone (T3) administration (150 mg/kg/day, i.p.) resulted in a shift towards a faster MHC profile in control rats and an attenuation of the shift towards L. slower profile in FO rats. HSP72 and CaN-A content were 63% and 47% higher, respectively, in the plantaris of FO than age-matched control rats. These increases were significantly attenuated by T3 treatment in FO rats. CaN-B levels were ~50% higher in FO and FO plus T3-treated than control rats. T3 treatment alone had no effect on the levels of HSP72. CaN-A or -B in control rats. Therefore, chronic overload of a muscle results in an increase in the percentage of slow fibers/MHC and enhances the levels of HSP72 and CaN. In turn, these FO-induced adaptations are attenuated by T3 treatment. Combined. these results indicate that muscle HSP72 and CaN protein levels are modulated by mechanical stress and that their levels appear to be related to changes in fiber type/MHC composition, at least in chronically overloaded muscles. 2005 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available