Hepatic Branched-Chain α-Keto Acid Dehydrogenase Complex in Female Rats: Activation by Exercise and Starvation

Rumi KOBAYASHI; Yoshiharu SHIMOMURA; Taro MURAKAMI; Naoya NAKAI; Megumi OTSUKA; Nobuhiko ARAKAWA; Kazuyuki SHIMIZU; Robert A. HARRIS

doi:10.3177/jnsv.45.303

Rumi KOBAYASHI, Yoshiharu SHIMOMURA, Taro MURAKAMI, Naoya NAKAI, Megumi OTSUKA, Nobuhiko ARAKAWA, Kazuyuki SHIMIZU, Robert A. HARRIS

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Keywords: branched-chain α-keto acid dehydrogenase (BCKDH) complex, BCKDH kinase, exercise, starvation, female rat liver

JOURNAL FREE ACCESS

1999 Volume 45 Issue 3 Pages 303-309

DOI https://doi.org/10.3177/jnsv.45.303

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Abstract

The effects of acute exercise and starvation on hepatic branched-chain α-keto acid dehydrogenase (BCKDH) complex activity were examined in female rats fed high (30%)- or low (8%)-protein diets. The total activity of the complex was significantly higher in the high protein-fed rats than in the low protein-fed rats but was not affected by acute exercise and starvation in either diet group. The proportion of the active form of BCKDH complex was less than 10% in both diet groups. Acute exercise and starvation markedly increased the active form of the complex in both diet groups. The activity of BCKDH kinase, which is responsible for inactivation of the BCKDH complex by phosphorylation, tended to be decreased by acute exercise and starvation in both diet groups. These results suggest that the activity of the BCKDH kinase is an important factor determining the proportion of the active form of BCKDH complex in exercise and starvation, and that the female rat is a useful model for studying the regulation of hepatic BCKDH complex activity.

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