FGF23 and chronic kidney disease: We previously showed that inflammation stimulates Fgf23 transcription in the bone which results in increased serum cFGF23 levels with only mild elevations in circulating levels of biologically active iFGF23 levels due to coupled activation of FGF23 cleavage mechanisms.8 Consistent with these effects,8 LCN2 administration mainly increased Fgf23 transcription and secretion of cFGF23 and had a very modest impact on serum iFGF23 levels in the non-CKD models in the present study.