Regulation by physical training of enzyme activity and gene expression of branched-chain 2-oxo acid dehydrogenase complex in rat skeletal muscle.
We examined the effects of short-term (5 weeks) and long-term (12 weeks) physical training on actual and total activities, protein content and mRNA abundance of branched-chain 2-oxo acid dehydrogenase complex in rat skeletal muscle. The actual and total activities were significantly increased approximately 60% and approximately 40%, respectively, by long-term training. No effects of short-term training on activities were observed. The increase in the total activity corresponded to increased protein content of the E1 alpha and E2 components of the complex. On the other hand, mRNA abundance for E1 alpha and E2 were not affected by the training, but that for E1 beta was slightly, but significantly increased by both short-term and long-term trainings. These divergent alterations of the message levels for the subunits of the complex suggest that posttranslational regulatory mechanisms determine the amount of the complex in skeletal muscle. Since the complex is located in the mitochondrial matrix space, mitochondrial biogenesis in response to the training was examined by determining the content of mitochondrial DNA in the muscle. The mitochondrial DNA was proportionally increased with the total activity as well as the protein content of the complex, suggesting that expression of branched-chain 2-oxo acid dehydrogenase complex in skeletal muscle in response to physical training is associated with mitochondrial biogenesis.
Fujii
H
H
Laboratory of Biochemistry of Exercise and Nutrition, University of Tsukuba, Japan.
Tokuyama
K
K
Suzuki
M
M
Popov
K M
KM
Zhao
Y
Y
Harris
R A
RA
Nakai
N
N
Murakami
T
T
Shimomura
Y
Y
D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007658:Ketone Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology*; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D009097:Multienzyme Complexes; D012333:RNA, Messenger; D007658:Ketone Oxidoreductases; D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D002950:Citrate (si)-Synthase