Details

Autor(en) / Beteiligte

• Mitchell, Christopher R
• Harris, M. Brennan
• Cordaro, Anthony R
• Starnes, Joseph W

Titel

Effect of body temperature during exercise on skeletal muscle cytochrome c oxidase content

Ist Teil von

• Journal of applied physiology (1985), 2002-08, Vol.93 (2), p.526-530

Ort / Verlag

Bethesda, MD: Am Physiological Soc

Erscheinungsjahr

2002

Quelle

MEDLINE

Beschreibungen/Notizen

• 1  Department of Kinesiology, Southwestern University, Georgetown 78626; and 2  Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas 78712 This study determined the role of body temperature during exercise on cytochrome- c oxidase (CytOx) activity, a marker of mitochondrial content, and mitochondrial heat shock protein 70   (mtHSP70), which is required for import of nuclear-coded preproteins. Male, 10-wk-old, Sprague-Dawley rats exercised identically for 9 wk in ambient temperatures of 23°C ( n  = 10), 8°C with wetted fur ( n  = 8), and 4°C with wetted fur and fan ( n  = 7). These conditions maintained exercising core temperature (T c ) at 40.4, 39.2, or 38.0°C (resting temperature), respectively. During weeks 3-9 , exercisers ran 5 days/wk up a 6% grade at 20 m/min for 60 min. Animals were housed at 23°C. Gastrocnemius CytOx activity in T c =38.0°C (83.5 ± 5.5 µatoms O · min 1 · g wet wt 1 ) was greater than all other groups ( P  < 0.05), exceeding sedentary ( n  = 7) by 73.2%. T c of 40.4 and 39.2°C also were higher than sedentary by 22.4 and 37.4%, respectively ( P  < 0.05). Quantification of CytOx content verified that the increased activity was due to an increase in protein content. In extensor digitorum longus, a nonactive muscle, CytOx was not elevated in T c  = 38.0°C. mtHSP70 was significantly elevated in gastrocnemius of T c  = 38.0°C compared with sedentary ( P  < 0.05) but was not elevated in extensor digitorum longus ( P  > 0.05). The data indicate that decreasing exercise T c may enhance mitochondrial biogenesis and that mtHSP70 expression is not dependent on temperature. endurance exercise; mitochondrial biogenesis; mitochondrial heat shock protein 70; glucose-regulated protein 75; rat