High Fat Diet Induces an Increase in the Direct Phosphorylation of Glycerol Which Can Contribute for the Increase in White Adipose Tissue Mass (575.2)

Triacylglycerol (TAG) synthesis in mammalian tissues requires a continuous glycerol‐3‐phosphate (G3P) generation for fatty acids esterification and TAG synthesis. The pathways of G3P generation were examined in retroperitoneal (RWAT) and epididymal (EWAT) adipose tissues from mice fed a high‐fat (HF) diet for 8 wk. After this period we evaluate the in vitro rates of glucose uptake and incorporation of 1‐[14C]pyruvate or U‐[14C]glycerol into TAG‐glycerol, and also the glycerol kinase (GyK) and P‐enolpyruvate carboxykinase (PEPCK‐C) activities in both tissues. Protein content was evaluated by western blot. The plasma glucose and insulin were measured by commercial kits. HF diet induced marked increase in body fat mass and in the plasma levels of glucose and insulin. HF diet feeding induced a marked increase in activity (3,4X and 2,5X) and content (42% and 87%) of GyK in RWAT and EWAT, accompanied by a higher TAG‐glycerol synthesis from glycerol in EWAT (47%), but not in RWAT. In contrast, there was a decrease in G3P generation via glycolysis in RWAT (71%) and EWAT (39%) and also a reduction in TAG‐glycerol synthesis from pyruvate (72 and 75%, respectively), without changes in the PEPCK activity and content in both tissues. HF diet induces loss of reciprocal changes in glyceroneogenesis and glycolysis for G3P generation, and seems to favour the direct phosphorylation of glycerol for TAG synthesis and increase in fat mass.Grant Funding Source: Supported by CAPES, FAPESP and CNPQ