Regulation of FGF23: Beyond Bone

Curr Osteoporos Rep. 2021 Dec;19(6):563-573. doi: 10.1007/s11914-021-00703-w. Epub 2021 Nov 10.


Purpose of review: Fibroblast growth factor 23 (FGF23) is a bone- and bone marrow-derived hormone that is critical to maintain phosphate homeostasis. The principal actions of FGF23 are to reduce serum phosphate levels by decreasing kidney phosphate reabsorption and 1,25-dihydroxyvitamin D synthesis. FGF23 deficiency causes hyperphosphatemia and ectopic calcifications, while FGF23 excess causes hypophosphatemia and skeletal defects. Excess FGF23 also correlates with kidney disease, where it is associated with increased morbidity and mortality. Accordingly, FGF23 levels are tightly regulated, but the mechanisms remain incompletely understood.

Recent findings: In addition to bone mineral factors, additional factors including iron, erythropoietin, inflammation, energy, and metabolism regulate FGF23. All these factors affect Fgf23 expression, while some also regulate FGF23 protein cleavage. Conversely, FGF23 may have a functional role in regulating these biologic processes. Understanding the bi-directional relationship between FGF23 and non-bone mineral factors is providing new insights into FGF23 regulation and function.

Keywords: Anemia; Fibroblast growth factor 23; Inflammation; Kidney injury; Metabolism; Phosphate.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Bone and Bones / metabolism
  • Energy Metabolism*
  • Erythropoiesis*
  • Fibroblast Growth Factor-23 / metabolism*
  • Homeostasis
  • Humans
  • Inflammation / metabolism*
  • Iron Deficiencies / metabolism*
  • Mice


  • FGF23 protein, human
  • Fibroblast Growth Factor-23