LCN2 and chronic kidney disease: In bone, cAMP is also an important mediator of PTH effects56,57 and we confirm that cAMP-mediated signaling is a potent regulator of FGF23 transcription.58 The fact that cAMP signaling is regulated by both PTH and LCN2 upstream of FGF23 production suggests that cAMP-mediated signaling may play a central role in the regulation of FGF23 in CKD.