Fig. 5.

Indirect contribution of oral glycerol to triglycerides. These results are based on analysis of TG-glycerol C2 that distinguishes glycerol indirect and direct contribution to triglycerides following [U–¹³C₃]glycerol administration. (A) In ¹³C NMR of TG-glycerol C2, a doublet (D) is the signal from [¹³C₂]glycerol backbone, reflecting labeled glycerol indirect contribution to triglycerides through the TCA cycle. A triplet (T) at this region is from [¹³C₃]glycerol backbone, reflecting the glycerol direct incorporation to triglycerides. (B) The percentage of [U–¹³C₃]glycerol indirect contribution to triglycerides remained unchanged in both groups. (C-D) Both indirect and direct glycerol incorporation to triglycerides decreased in the empagliflozin group with low VAT after treatment based on the quantitation of TG-[¹³C₂]glycerol and TG-[¹³C₃]glycerol, respectively. Open circle = ¹²C; black circle = ¹³C; blue circle = ¹³C after metabolism through the TCA cycle. *, p < 0.05; n = 16 in the placebo group (8 with low VAT & 8 with high VAT); n = 15 in the empagliflozin group (7 with low VAT & 8 with high VAT). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)