The low sensitivity of 13C spectroscopy can be enhanced using dynamic nuclear polarization. Detection of hyperpolarized [1- 13C]pyruvate and its metabolic products has been reported in kidney, liver, and muscle. In this work, the feasibility of measuring 13C signals of hyperpolarized 13C metabolic products in the rat brain in vivo following the injection of hyperpolarized [1-13C]pyruvate and [2-13C]pyruvate is investigated. Injection of [2-13C] pyruvate led to the detection of [2-13C]lactate, but no other downstream metabolites such as TCA cycle intermediates were detected. Injection of [1-13C]pyruvate enabled the detection of both [1- 13C]lactate and [13C]bicarbonate. A metabolic model was used to fit the hyperpolarized 13C time courses obtained during infusion of [1-13C]pyruvate and to determine the values of V PDH and VLDH.
Bibliographical noteFunding Information:
The authors thank Manda Vollmers, Dee Koski, and William Mander from Oxford Instruments Molecular Biotools for technical support, Michael G. Garwood for helpful discussion about adiabatic pulses, and Josef Granwehr and Jamie D. Walls for comments about the paper. This work was supported by BTRR – P41 RR008079, P30 NS057091, RO1-NS38672, and the W.M. Keck Foundation. The high-resolution NMR facility at the University of Minnesota is supported with funds from the NSF (BIR-961477), the University of Minnesota Medical School, and the Minnesota Medical Foundation.
- Time courses