Effect of Fatty Liver on TCA Cycle Flux and the Pentose Phosphate Pathway

The investigators plan to determine whether nutritional state and fatty liver influence the production of \[13C\]bicarbonate from \[1-13C\]pyruvate via flux through the pyruvate dehydrogenase (PDH) reaction in healthy subjects compared to those with fatty liver. The long-term purpose of this work is to develop hyperpolarized 13C imaging as a method to directly assess metabolic pathways in the human liver. Many high-impact diseases such as insulin resistant states, fatty liver and inborn errors of metabolism are known to alter biochemical fluxes and for this reason it is important to detect altered activity in specific pathways.