The three alkyglycerol lipids (AKGs) shown are the ones that are present in human breast milk. These are converted into signaling lipids, platelet-activating factor (PAF), by macrophages found in fat tissue in newborns. Macrophages then respond to PAF by producing a signaling protein (interleukin 6). Interleukin 6 controls beige fat cell development.
Read more:
N. R. Gough, Signal or Nutrient: Breast Milk Lipids in Macrophages. BioSerendipity (December 2019) https://www.bioserendipity.com/signal-or-nutrient-breast-milk-lipids-in-macrophages
N. R. Gough, Researchers Find a Special Lipid that Controls Fat Development in Babies. Medium (18 October 2019).