["The Journal of Physiology, Volume 604, Issue 11, Page 4564-4584, 1 June 2026. ", "\nAbstract figure legend Metabolic early response in macrophages exposed to palmitic acid. After 3 h of exposition with palmitic acid, macrophages induced a series of metabolic changes to counteract the palmitic acid overload. Between these changes, we found that the glycerol 3‐phosphate shuttle is partially inhibited to divert glucose‐derived metabolites for triacylglycerol biosynthesis. Also, we found that the glycerol transporter, aquaporin 3 (AQP3) is overexpressed under these conditions. Both mechanisms are used to devote glycerol 3‐phosphate for triacylglycerol biosynthesis. Interestingly, we also observed that AQP3 is overexpressed in adipose tissue macrophages from a mice model of cardiometabolic heart failure.\n\n\n\n\n\n\n\n\n\nAbstract\nMacrophages chronically exposed to saturated fatty acids, such as those encountered in adipose tissue, present a pro‐inflammatory phenotype with a characteristic foamy morphology. This feature is caused by the excess uptake of circulating lipids, yielding large cytoplasmic lipid bodies formed by triacylglycerols and cholesteryl derivatives. Palmitic acid (PA) is a potent inflammatory inducer in macrophages after chronic exposure to this fatty acid. However, acute exposure to this fatty acid is unable to activate a pro‐inflammatory phenotype, although it is sufficient to induce metabolic reprogramming including the formation of small lipid bodies. In the present study, we used an in vitro model of human monocyte‐derived macrophages to unravel the early stages of metabolic reprogramming observed in macrophages exposed to PA. We observed that partial inhibition of the glycerol 3‐phosphate shuttle is necessary for supplying glycerol 3‐phosphate for triacylglycerol biosynthesis. Furthermore, we characterized an alternative pathway to increase the concentration of glycerol 3‐phosphate involving an aquaporin and glycerol kinase. Our results suggested that early lipid bodies biogenesis rises as a response mechanism to buffer excessive PA without inducing a pro‐inflammatory program. Additionally, we observed that macrophages chronically exposed to PA eventually upregulate the production of inflammatory cytokines. Finally, our in vitro observations were confirmed in adipose tissue macrophages derived from a preclinical mouse model of cardiometabolic heart failure with preserved ejection fraction characterized by heightened adiposity and inflammation.\n\n\n\n\n\n\n\n\n\nKey points\n\nThe glycerol 3‐phosphate shuttle is partially inhibited in palmitic acid‐activated macrophages.\nAquaporin 3 expression is upregulated in macrophages exposed to palmitic acid and in adipose tissue macrophages from a murine model of cardiometabolic heart failure.\nAquaporin 3 participates in the biosynthesis of triacylglycerols by supplying extracellular glycerol.\n\n\n"]