Stimulatory effect of cold acclimation on skeletal muscle branched-chain α-keto acid dehydrogenase in rats

2002 ◽  
Vol 73 (5) ◽  
pp. 363-368
Author(s):  
Masaaki TOYOMIZU ◽  
Tsunekazu AKAZAWA ◽  
Hisao FUJII ◽  
Naoya NAKAI ◽  
Yoshiharu SHIMOMURA ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cold Acclimation ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Branched Chain

scholarly journals Branched-chain α-keto acid dehydrogenase kinase content in rat skeletal muscle is decreased by endurance training

IUBMB Life ◽  
1998 ◽  
Vol 44 (6) ◽  
pp. 1211-1216 ◽  
Author(s):  
Hisao Fujii ◽  
Yoshiharu Shimomura ◽  
Taro Murakami ◽  
Naoya Nakai ◽  
Tasuku Sato ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Keto Acid ◽  
Rat Skeletal Muscle ◽  
Acid Dehydrogenase ◽  
Branched Chain

Effects of diabetes and starvation on skeletal muscle branched-chain alpha-keto acid dehydrogenase activity

1988 ◽  
Vol 254 (3) ◽  
pp. E292-E300 ◽  
Author(s):  
R. P. Aftring ◽  
W. J. Miller ◽  
M. G. Buse
Keyword(s):  
Skeletal Muscle ◽  
Insulin Treatment ◽  
Branched Chain Amino Acids ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Hindlimb Muscles ◽  
Activation Response ◽  
Branched Chain ◽  
Persistent Elevation ◽  
Significant Activation

The activation state of branched-chain alpha-keto acid dehydrogenase (BCDH) was studied in rat hindlimb muscles during starvation and insulinopenic diabetes, conditions in which circulating branched-chain amino acids (BCAA) are increased and their oxidation is accelerated. Muscle BCDH is predominantly inactive (phosphorylated) in postabsorptive rats but is activated by increased circulating leucine. Diabetes (streptozotocin-induced and spontaneous BB/W) increased circulating BCAA four- to fivefold and BCDH activity approximately threefold. Insulin treatment caused near normalization of circulating BCAA without correcting BCDH activity. Adrenalectomy of diabetics decreased (without normalizing) circulating BCAA and BCDH activation. Starvation caused mild, progressive increases in circulating BCAA and significant activation of BCDH only after 4 days. Leucine infusion activated BCDH in muscle but the activation by leucine was markedly blunted by diabetes. In isolated perfused hindlimbs (control and diabetic) insulin did not affect BCDH significantly; perfusion with leucine activated BCDH, and this response appeared blunted in diabetics. Activation of muscle BCDH may contribute to increased BCAA catabolism in diabetes; the blunted activation response to hyperleucinemia may spare BCAA and contribute to their persistent elevation in plasma.

Glucocorticoid-mediated activation of muscle branched-chain alpha-keto acid dehydrogenase in vivo

1987 ◽  
Vol 252 (3) ◽  
pp. E396-E407 ◽  
Author(s):  
K. P. Block ◽  
W. B. Richmond ◽  
W. B. Mehard ◽  
M. G. Buse
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Active Enzyme ◽  
Acid Oxidation ◽  
Enzyme Complex ◽  
Keto Acid ◽  
Amino Acid Oxidation ◽  
Acid Dehydrogenase ◽  
Branched Chain Amino Acid ◽  
Branched Chain

Muscle branched-chain alpha-keto acid dehydrogenase, the rate-limiting enzyme for branched-chain amino acid oxidation in skeletal muscle, was measured after treatment of rats with glucocorticoids. Cortisone treatment (10 mg X 100 g body wt-1 X day-1 for 2–5 days) resulted in an approximate doubling of the percentage of active enzyme. To further characterize this effect, the enzyme complex was measured 4 h after the intraperitoneal injection of 6 alpha-methylprednisolone, a water-soluble glucocorticoid with rapid onset effects. The percentage of active enzyme increased linearly as the dose of methylprednisolone was increased from 0.125 to 12.5 mg/100 g body wt, while total enzyme activity was unchanged. Administration of insulin with glucose had no significant effect on the activity of the enzyme. However, treatment of rats with insulin and glucose after methylprednisolone administration partially blocked branched-chain alpha-keto acid dehydrogenase activation. The activity of the enzyme complex was correlated with the concentration of leucine in plasma and muscle. Activation of skeletal muscle branched-chain alpha-keto acid dehydrogenase by increased glucocorticoids may play a role in the acceleration of branched-chain amino acid oxidation observed during severe stress.

Leucine and isoleucine activate skeletal muscle branched-chain alpha-keto acid dehydrogenase in vivo

1986 ◽  
Vol 250 (5) ◽  
pp. E599-E604 ◽  
Author(s):  
R. P. Aftring ◽  
K. P. Block ◽  
M. G. Buse
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Total Activity ◽  
Branched Chain Amino Acids ◽  
Keto Acid ◽  
Muscle Enzyme ◽  
Phosphatase Inhibitors ◽  
Acid Dehydrogenase ◽  
Branched Chain

The response of rat skeletal muscle branched-chain alpha-keto acid dehydrogenase to administration of branched-chain amino acids in vivo was determined using a soluble preparation of the enzyme. After detergent extraction of the complex in the presence of kinase and phosphatase inhibitors, initial in vivo activity was typically 1 nmol X min-1 X g muscle-1, with 0.1 mM alpha-[1-14C]ketoisocaproate as substrate. Total activity of the dephosphorylated complex, measured after preincubation with 15 mM Mg2+, typically reached a maximum of 29 nmol X min-1 X g-1. Thus in overnight-fasted rats the complex was 2-3% active. Initial activity increased three- to fivefold after leucine or isoleucine (at higher concentrations) but not valine administration in vivo. After intravenous leucine injection (0.25 mmol/kg) initial muscle enzyme activity increased rapidly and subsequently decreased, paralleling plasma leucine concentrations, while plasma valine and isoleucine decreased. In conclusion, muscle branched-chain alpha-keto acid dehydrogenase complex is rapidly activated when circulating leucine is increased to concentrations that may occur after meals. During hyperleucinemia accelerated valine and isoleucine degradation by muscle may account for the observed "antagonism" among the branched-chain amino acids.

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