A stable isotope technique for investigating lactate metabolism in humans.

A stable isotope tracer method has been developed for studying lactate metabolism in humans. The method uses lactic acid triple labeled with 13C as the tracer. The stable isotope is infused to attain a level of approximately 1.5% of that of the circulating unlabeled lactate. Following the isolation of lactic acid from the blood, the percentage of triple labeled (13C)lactate is measured using gas chromatography mas spectrometry. We compared this method with tracer methodology using [14C]lactate and found comparable results.