Hepatocytes isolated from rats fed on a chow diet or a low-protein (8% ) diet were used to study the effects of various factors on flux through the branched-chain 2-oxo acid dehydrogenase complex. The activity of this complex was also determined in cell-free extracts ofthe hepatocytes. Hepatocytes isolated from chow-fed rats had greater flux rates (decarboxylation rates of3-methyl-2-oxobutanoat...