Branched-chain-ketoacid metabolism in patients with chronic renal failure

Branched-chain ketoacids (BCKAs) were determined in fasting plasma samples from 19 patients with chronic renal failure (CRF). Ketomethylvalerate (KMV) was significantly higher in patients receiving BCKA supplements, presumably reflecting accumulation of the R(-) isomer. Mean levels of all three BCKAs were not significantly different from normal. However, multiple-regression analysis showed that plasma ketoisocaproate was strongly correlated with glomerular filtration rate (GFR), negatively correlated with serum triglyceride concentration, and positively correlated with protein intake. KMV concentration was also correlated positively with GFR, negatively with triglyceridemia, and positively with serum total carbon dioxide. Ketoisovalerate concentration did not vary with GFR and was not predictable from the regressors used. Single oral doses of a mixture containing all three BCKAs led to the same areas under the three plasma concentration curves in patients with CRF as in normal subjects, indicating that absorption of all three BCKAs after oral administration in patients with CRF is unimpaired.