Publication: Regular exercise improves cardiac contractile activation by modulating MHC isoforms and SERCA activity in orchidectomized rats
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Issued Date
2015-01-01
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ISSN
15221601
87507587
87507587
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2-s2.0-84943792286
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Applied Physiology. Vol.119, No.7 (2015), 831-839
Suggested Citation
Pavarana Vutthasathien, Jonggonnee Wattanapermpool Regular exercise improves cardiac contractile activation by modulating MHC isoforms and SERCA activity in orchidectomized rats. Journal of Applied Physiology. Vol.119, No.7 (2015), 831-839. doi:10.1152/japplphysiol.00224.2015 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/35526
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Title
Regular exercise improves cardiac contractile activation by modulating MHC isoforms and SERCA activity in orchidectomized rats
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Abstract
© 2015 the American Physiological Society. Data from the trial known as Testosterone in Older Men with Mobility Limitations (TOM) has indicated an association between testosterone administration and a greater risk for adverse cardiovascular events. We therefore propose that regular exercise is a cardioprotective alternative that prevents detrimental changes in contractile activation when a deficiency in male sex hormones exists. Ten-week-old orchidectomized (ORX) rats were subjected to a 9-wk treadmill running program at moderate intensity starting 1 wk after surgery. Although exercise-induced cardiac hypertrophy was observed both in rats that underwent ORX and sham surgery, regular exercise enhanced cardiac myofilament Ca2+sensitivity and myosin light-chain 2 phosphorylation only in rats that underwent a sham operation. Although the rats that had sham surgery and and given exercise exhibited no change in maximum developed tension, regular running prevented the suppression of maximum active tension in the hearts of ORX rats. Regular exercise also prevented a shift in myosin heavy chain (MHC) isoforms toward β-MHC, a reduction in sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity, and an increase in SERCA sensitivity in the hearts of ORX rats. Neither SERCA content nor its modulating component, phospholamban (PLB), was altered by exercise in either sham-operated or ORX rats. However, decreases in the phosphorylated Thr17form of PLB and the phosphorylated Thr287form of Ca2+/calmodulindependent kinase II in the hearts of ORX rats were abolished after regular exercise. These results thus support the use of regular running as a cardioprotective alternative to testosterone replacement in hypogonadal conditions.