Metabolism of D-lactate in the dog and in man

Peritoneal fluid contains equimolar amounts of D- and L-isomers of lactate. Controversy exists as to whether D-lactate is metabolized as effectively as the L- isomer. D- and L-lactate were infused into the portal circulation of dogs and net hepatic uptake of both isomers measured by A-V sampling, blood flows being measured by flow probes. Hepatic extractions of both isomers were not significantly different. In three patients on intermittent peritoneal dialysis (IPD), and three patients on continuous ambulatory peritoneal dialysis (CAPD), arterial D-lactate was less than 15% of the concentration of L-lactate at the end of treatment. In conclusion, D-lactate is metabolized as effectively as L-lactate.