Fig. 2
From: FGF23-Klotho axis in CKD
The activities of FGF23 in the kidney. FGF23 reduces serum phosphate level by suppressing the expression of type 2a and 2c sodium-phosphate cotransporters in the renal proximal tubules. In addition, FGF23 decreases intestinal phosphate absorption by reducing 1,25(OH)2D level via not only suppressing CYP27B1 which produces 25-hydroxyvitamin D-1α-hydroxylase but also enhancing CYP24A1 expression encoding 25-hydroxyvitamin D-24-hydroxylase