Figure 3.

Carnitine can modulate in vivo cardiac metabolism. In vivo effects on cardiac metabolism by infusion of hyperpolarized [1-¹³C]pyruvate and [2-¹³C]pyruvate. (A) Example [1-¹³C]pyruvate spectrum acquired from the in vivo rat heart. (B) Example [2-¹³C]pyruvate spectrum acquired from the in vivo rat heart. (C) Bicarbonate + CO₂/pyruvate ratio, as a measure of pyruvate dehydrogenase (PDH) flux. (D) Lactate/pyruvate ratio. (E) Alanine/pyruvate ratio. (F) Citrate/pyruvate ratio normalized to PDH flux. (G) Glutamate/pyruvate ratio normalized to PDH-flux. (H) Acetylcarnitine/pyruvate ratio normalized to PDH-flux. Data are presented as mean ± SD. Two-way ANOVA, if an interaction was found to be significant, the effect of L-carnitine on control and diabetes was evaluated using Sidak’s multiple comparison test. Significant differences are represented by ‘*’, with * p < 0.05, ** p < 0.01, **** p < 0.0001.