Branched-chain keto acid metabolism in the isolated perfused rat heart

Letto, Joan (1989) Branched-chain keto acid metabolism in the isolated perfused rat heart. Masters thesis, Memorial University of Newfoundland.

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Abstract

The Langendorff once-through perfusion system was used to investigate the metabolism of branched-chain amino acids in rat heart. The effects of branched-chain amino acids on fatty acid metabolism was studied. The ketoacid of leucine (KIC) inhibited the oxidation of oleate in the perfused heart. Although the ketoacids of valine (KIV) and isoleucine (KIL) were decarboxylated in cardiac muscle, they did not affect fatty acid oxidation. This appears to be due to the fact that KIC is almost completely oxidized in the heart, whereas only 19% of KIV is completely oxidized. -- 3-Hydroxyisobutyrate, an intermediate in ketovaline metabolism, was shown to be released from heart when KIV was the substrate. 3-Hydroxyisobutyrate was shown to be a substrate for gluconeogenesis in isolated kidney cortical tubules and hepatocytes.

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