[3-13C]Pyruvate: Useful Alternative to labeled Glucose for in vitro Metabolic Studies in Primary Mouse Hepatocytes

The application of stable isotope labeling in cell culture experiments is a widely used and potent model for the study and characterization of metabolic pathways and fluxes. In particular, incorporation of 13C-labels at certain carbon positions of a given metabolite may not only provide important information about pathways and fluxes but may even reveal unexpected metabolic phenomena without prior knowledge. Depending on the cellular model and the area of interest, one has to take into consideration which labeled substrate will give the most valuable information. Primary hepatocytes in cell culture – a widely used model to study liver physiology and diseases – are expected to use a variety of substrates for their cellular and energy metabolism. So far, 13C-NMR studies have been rarely performed in isolated hepatocytes. Labeled glucose is the most widely used substrate in cells isolated from various organs. However, we have shown in preliminary experiments that hepatocytes in primary culture do not readily metabolize glucose taken up from the medium. Since hepatocytes have a very high mitochondrial activity, we have therefore decided to use one- and two-dimensional multinuclear NMR-spectroscopy to characterize the metabolism of [3-13C]pyruvate and the metabolic isotopomers derived trough various pathways in these cells