Figure 3.

NMR analysis of lipid extracts from the liver. (a) [U‐¹³C₃]glycerol direct incorporation to triglycerides (TG) produces triple‐labeled ([U‐¹³C₃]) glycerol backbones. [U‐¹³C₃]glycerol metabolism through the TCA cycle prior to TG produces double‐labeled backbones. (b) ¹³C NMR of lipid extracts shows signals from the glycerol backbones of triglycerides (TG‐glycerol), cholesterol, cholesterol ester (CE), phosphatidylcholine (PC), and fatty acids. Multiplets at TG‐glycerol demonstrate [U‐¹³C₃]glycerol incorporation to TG. (c and d) The levels of TG and TG‐[¹³C]glycerol in the liver were similar between controls and acetaminophen‐treated animals. (e) The fraction of TG‐[¹³C₂]glycerol tended to be reduced in acetaminophen‐treated animals without a statistical significance. The double‐labeled backbones of TG were produced through [U‐¹³C₃]glycerol metabolism in the TCA cycle. (f) The concentrations of fatty acids remained unchanged with acetaminophen treatment. Abbreviations: D at C1 and C3, [U‐¹³C₃]‐, [1,2‐¹³C₂]‐, and [2,3‐¹³C₂]glycerol; D at C2, [1,2‐¹³C₂]‐ and [2,3‐¹³C₂]glycerol; S, [2‐¹³C₁]glycerol at C2 or [1‐¹³C₁]‐ and [3‐¹³C₁]glycerol at C1 and C3; T at C2, [U‐¹³C₃]glycerol; G3P, glycerol 3‐phosphate; open circle, ¹²C; black circle, ¹³C; blue circle, ¹³C after experiencing the TCA cycle; n = 3 in each group