In Vivo Measurement of Normal Rat Intracellular Pyruvate & Lactate Levels After Injection of Hyperpolarized [1-13C]Alanine

Simon Hu¹, Hikari Yoshihara¹, Robert Bok¹, Peder E. Larson¹, John Kurhanewicz¹, Daniel B. Vigneron¹

The most commonly used in vivo agent in hyperpolarized ¹³C metabolic imaging thus far has been [1-¹³C]pyruvate. In preclinical studies, not only is its uptake detected but also its intracellular enzymatic conversion to metabolic products including [1-¹³C]lactate. However, the ratio of ¹³C-lactate/¹³C-pyruvate measured in this data does not accurately reflect cellular values since much of the [1-¹³C]pyruvate is extracellular depending on timing, vascular properties and extracellular space and monocarboxylate transporter activity. In order to measure the relative levels of intracellular pyruvate and lactate, in this project we hyperpolarized [1-¹³C]alanine and monitored the in vivo conversion to [1-¹³C]pyruvate and [1-¹³C]lactate.