The blood lactate/pyruvate equilibrium affair

The Lactate Shuttle hypothesis is supported by a variety of techniques including mass spectrometry analytics following infusion of carbon-labeled isotopic tracers. However, there has been controversy over whether lactate tracers measure lactate (L) or pyruvate (P) turnover. Here, we review the analytical errors, use of inappropriate tissue and animal models, failure to consider L and P pool sizes in modeling results, inappropriate tracer and blood sampling sites, and failure to anticipate roles of heart and lung parenchyma on L () P interactions. With support from magnetic resonance spectroscopy (MRS) and immunocytochemistry, we conclude that carbon-labeled lactate tracers can be used to quantitate lactate fluxes.

Automated summary

The Lactate Shuttle hypothesis is supported by various techniques, but there has been controversy over whether lactate tracers measure lactate or pyruvate turnover. In this review, the authors discuss the analytical errors, inappropriate models and methods, as well as the roles of heart and lung parenchyma in lactate-pyruvate interactions. With support from magnetic resonance spectroscopy and immunocytochemistry, the authors conclude that carbon-labeled lactate tracers can be used to measure lactate fluxes.