Deuterium distribution in lactate as tracer of metabolic pathways

2H-NMR spectroscopy has been used to study the distribution of2H atoms in brain lactate, after intraperitoneal injection of2H2O. Information on brain metabolism was obtained from the ratio [(3-2H)lactate]/[(2-2H)lactate] which was found very sensitive to the PO2in the breathing air. The dependence of this ratio on the rates of metabolic pathways is an example of the possibility to use the distribution of2H atoms in a molecule to probe metabolic flow through different pathways.