SGK1 and chronic kidney disease: After the treatment of FPS or CTR for 3 weeks, the changed protein expression levels of p-ERK1/2, p-SGK1, NHERF-1 and NaPi-2a in the kidneys of the CKD–MBD model rats were ameliorated obviously, compared to those of the CKD–MBD group rats (Figures 7B–E).