| Abstract: | Branched-chain amino acid metabolism in hemidiaphragms from 40 h-starved rats is influenced by the provision of glucose as co-substrate. Glucose inhibits 14CO2 production from l-14C]valine and U-14C]valine but stimulates 14CO2 production from l-14C]leucine, U-14C]leucine and U-14C]isoleucine. In the presence of glucose, ketone bodies inhibit alanine release and 14CO2 production from l-14C]valine, l-14C]leucine and U-14C]isoleucine, but inhibition is not observed in the absence of glucose as cosubstrate. Glucose-dependent inhibition by ketone bodies of branched-chain amino acid oxidation via inhibition of the branched-chain 2-oxo acid dehydrogenase complex or branched-chain amino acid aminotransferase may account in part for the reported hypoalanaemic action of ketone bodies in vivo. |
