Karlos X. Moreno1, Scott Sabelhaus1, Matthew E. Merritt1,2, A Dean Sherry1,3, Craig R. Malloy1,4
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Tx, USA; 2Dept of Radiology, UT Southwestern Medical Center, Dallas, Tx, USA; 3Dept of Chemistry, Univ. of Texas at Dallas, Dallas, Tx, USA; 4Dept of Internal Medicine, UT Southwestern Medical Center, Dallas, Tx, USA
The heart oxidizes many substrates. The [pyruvate] necessary to compete effectively with long chain fatty acids, ketones, glucose and lactate was studied in rat hearts supplied with mixtures of substrates that mimic the fed or fasted state. 13C NMR isotopomer analysis showed that [pyruvate] even at 3 mM was oxidized at a high rate compared to fatty acids or ketones but a higher [pyruvate] was required under fasted state conditions. A transient reduction in cardiac output was observed at [pyruvate] > 10 mM. A minimum [pyruvate] of 3-6 mM would likely be required for cardiac exams.