Fibroblast growth factor (FGF) 23 inhibits calcitriol production, which could exacerbate
calcium deficiency or hypocalcemia unless calcium itself modulates FGF23 in this setting. In
Wistar rats with normal renal function fed a diet low in both calcium and vitamin D, the
resulting hypocalcemia was associated with low FGF23 despite high parathyroid hormone
(PTH) and high calcitriol levels. FGF23 correlated positively with calcium and negatively with
PTH. Addition of high dietary phosphorus to this diet increased FGF23 except in rats with …