FGFR1 and chronic kidney disease: Plasma PTH levels increased significantly in CKD mice: Fgfr1–3flox/flox, control (122.6 ± 84.3 pg/mL, n = 12) vs CKD (3264.7 ± 1654.5 pg/mL, n = 10), P < 0.001; αKlothoflox/flox, control(182.6 ± 87.0 pg/mL, n = 7) vs CKD (2452.4 ± 425.9 pg/mL, n = 9) P < 0.001; Fgfr1–4flox/flox, control (357.2 ± 210.8 pg/mL, n = 7) vs CKD (2226.8 ± 801.8 pg/mL, n = 8) P < 0.001.