FGF21 and hydrops fetalis: Finally, we characterised transcriptional regulatory pathways and AMPKα as targets for possible underlying mechanisms of n-3 LCPUFA, whereby FGF21 might mediate the metabolic effects of HF/n-3 in iBAT, and the increase in rather anti-inflammatory macrophages and eosinophils can be associated with lipid buffering and even thermogenesis in iBAT.