FGF23 and chronic kidney disease: Mice with cardiomyocyte-specific deletion of FGFR4 do not develop LVH in response to repeated short-term (5 days) FGF23 injections.13 To determine if FGF23 and cardiac FGFR4 contribute to cardiac metabolic remodeling in CKD, we created mice with inducible cardiomyocyte-specific deletion of FGFR4 (α-MHCMerCreMer-FGFR4flox).