Interaction of octanoate with branched-chain 2-oxo acid oxidation in rat and human muscle in vitro.
Acetate and butanoate inhibited and hexanoate and octanoate increased the 14CO2 production from 0.1 mM [1-14C]-labelled 2-oxoisocaproate (KIC) and 2-oxoisovalerate (KIV) in rat hemidiaphragms. Octanoate increased KIC and KIV oxidation in rat soleus muscle, too, inhibited it in human skeletal muscle and had a divergent effect in rat and human heart slices. In rat hemidiaphragms octanoate primarily affected the process of oxidative decarboxylation. No effect was found on transamination rates of branched-chain amino acids and on the CO2 production beyond alpha-decarboxylation. The reverse transamination of branched-chain 2-oxo acids and their incorporation into protein decreased in the presence of octanoate. Octanoate had no effect on KIC and KIV oxidation at higher 2-oxo acid concentrations and in hemidiaphragms from 3-day-starved rats. The observed interactions are discussed and related to regulatory mechanisms, which are known to affect the branched-chain 2-oxo acid dehydrogenase complex.
D000214:Acyl Coenzyme A / Q000378:metabolism; D000597:Amino Acids, Branched-Chain / Q000378:metabolism; D000818:Animals; D002210:Caprylates / Q000494:pharmacology*; D005508:Food Deprivation; D045782:Hemiterpenes; D006801:Humans; D007651:Keto Acids / Q000378:metabolism*; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats
D000214:Acyl Coenzyme A; D000597:Amino Acids, Branched-Chain; D002210:Caprylates; D045782:Hemiterpenes; D007651:Keto Acids; C001505:alpha-ketoisovalerate; C013082:alpha-ketoisocaproic acid