Figure 4. Results from the in vivo experiments.

(A and B) Typical example of the total lipid spectrum, acquired with STEAM (stimulated echo acquistion mode) ¹H-MRS, and the concomitant ¹³C-edited lipid spectrum, acquired with the ge-HSQC (heteronuclear single quantum coherence) sequence. As no decoupling was applied, two lipid CH₂ peaks are visible, which are separated by approximately 127 Hz. (C) The total IHL (intrahepatic lipid) pool (g/kg ww) for both lean (n = 5) and obese (n = 6) subjects at 1,5, 3.0, 4.5, and 6.0 hours after a high-fat meal. Total IHL did not change after the meal (repeated-measures ANOVA, P = 0.35). (D) The absolute concentration of ¹³C lipids (g/kg ww) in the liver is plotted in time, showing retention of ¹³C-labeled fatty acids after the meal (repeated-measures ANOVA, P < 0.01).