AJP - Endocrinology and Metabolism, Vol 267, Issue 3 E388-E395, Copyright © 1994 by American Physiological Society

ARTICLES

Enzymatic and genetic adaptation of soleus muscle mitochondria to physical training in rats

T. Murakami, Y. Shimomura, N. Fujitsuka, N. Nakai, S. Sugiyama, T. Ozawa, M. Sokabe, S. Horai, K. Tokuyama and M. Suzuki
Department of Bioscience, Nagoya Institute of Technology, Japan.

To evaluate the effects of physical training on mitochondrial gene expression and mitochondrial biogenesis in slow-twitch muscle, adult female Sprague-Dawley rats were trained for 3, 6, and 12 wk by running on a motor-driven treadmill (speed of 25 m/min and duration of 90 min/day, 5 days/wk), and the activities of citrate synthase, ubiquinol-cytochrome-c oxidoreductase, cytochrome oxidase, mitochondrial cytochrome b mRNA (by Northern blot analysis), and mitochondrial DNA (by slot-blot and Southern blot analyses) were measured in rat soleus muscle. A DNA probe for detection of mitochondrial mRNA and DNA was prepared from a 1,500-bp fragment of human mitochondrial DNA that included the coding region of the cytochrome b gene. Training for 3, 6, and 12 wk significantly increased the activities of citrate synthase (31, 28, and 47%, respectively), ubiquinol-cytochrome-c oxidoreductase (61, 63, and 77%, respectively), and cytochrome oxidase (25, 26, and 32%, respectively) in muscle. The concentration of cytochrome b mRNA in the muscle was proportionally elevated with the enzyme activities. On the other hand, the mitochondrial DNA concentration in the muscle was not altered by training for 3 or 6 wk but increased significantly after training for 12 wk (35% in the slot-blot analysis and 31% in the Southern blot analysis). These results suggest that an increase in the oxidative capacity of slow-twitch muscle by the relatively short-term training is regulated at the pretranslational step in mitochondrial protein synthesis but that the increase by the long-term training involves mitochondrial replication.

This article has been cited by other articles:

				G. D. Wadley, R. J. Tunstall, A. Sanigorski, G. R. Collier, M. Hargreaves, and D. Cameron-Smith Differential effects of exercise on insulin-signaling gene expression in human skeletal muscle J Appl Physiol, February 1, 2001; 90(2): 436 - 440. [Abstract] [Full Text] [PDF]

				R. Barazzoni, K. R. Short, and K. S. Nair Effects of Aging on Mitochondrial DNA Copy Number and Cytochrome c Oxidase Gene Expression in Rat Skeletal Muscle, Liver, and Heart J. Biol. Chem., February 4, 2000; 275(5): 3343 - 3347. [Abstract] [Full Text] [PDF]

				S. M. Hughes, M. M.-Y. Chi, O. H. Lowry, and K. Gundersen Myogenin Induces a Shift of Enzyme Activity from Glycolytic to Oxidative Metabolism in Muscles of Transgenic Mice J. Cell Biol., May 3, 1999; 145(3): 633 - 642. [Abstract] [Full Text] [PDF]

				B. J. Battersby and C. D. Moyes Influence of acclimation temperature on mitochondrial DNA, RNA, and enzymes in skeletal muscle Am J Physiol Regulatory Integrative Comp Physiol, September 1, 1998; 275(3): R905 - R912. [Abstract] [Full Text] [PDF]

				T. Murakami, Y. Shimomura, N. Fujitsuka, M. Sokabe, K. Okamura, and S. Sakamoto Enlargement of glycogen store in rat liver and muscle by fructose-diet intake and exercise training J Appl Physiol, March 1, 1997; 82(3): 772 - 775. [Abstract] [Full Text] [PDF]