Hyperphosphatemia, iron deficiency/anemia, and inflammation are potent stimuli of bone FGF23 production during CKD progression.2,8 We tested whether Lcn2 deletion would alter FGF23 regulation by phosphate, iron, or inflammatory stimuli induced by dietary Pi loading, iron restriction, and acute IL1β injections, respectively. This evidence concerns the gene IL1B and hyperphosphatemia.