Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
J Clin Endocrinol Metab. 2009 Jul;94(7):2332-7. doi: 10.1210/jc.2008-2396. Epub 2009 Apr 14.

FGF23 elevation and hypophosphatemia after intravenous iron polymaltose: a prospective study.

Author information

  • 1Department of Endocrinology, Christchurch Hospital, Christchurch, New Zealand. Belinda.Robb@cdhb.govt.nz

Abstract

CONTEXT:

Parenteral iron administration has been associated with hypophosphatemia. Fibroblast growth factor 23 (FGF23) has a physiological role in phosphate homeostasis via suppression of 25-hydroxyvitamin D [25(OH)D] activation and promotion of phosphaturia. We recently reported a case of iron-induced hypophosphatemic osteomalacia associated with marked FGF23 elevation.

OBJECTIVE:

Our objective was to prospectively investigate the effect of parenteral iron polymaltose on phosphate homeostasis and to determine whether any observed change was related to alterations in circulating FGF23.

DESIGN, SETTING, AND PARTICIPANTS:

Eight medical outpatients prescribed iv iron polymaltose were recruited. Plasma phosphate, 25(OH)D, 1,25-dihydroxyvitamin D [1,25(OH)(2)D], PTH, FGF23, and urinary tubular reabsorption of phosphate were measured prior to iron administration and then weekly for a minimum of 3 wk.

RESULTS:

Plasma phosphate fell from 3.4 +/- 0.6 mg/dl at baseline to 1.8 +/- 0.6 mg/dl at wk 1 (P < 0.0001) associated with a fall in percentage tubular reabsorption of phosphate (90 +/- 4.8 to 68 +/- 13; P < 0.001) and 1,25(OH)(2)D (54 +/- 25 to 9 +/- 8 pg/ml; P < 0.001). These indices remained significantly suppressed at wk 2 and 3. 25(OH)D levels were unchanged. FGF23 increased significantly from 43.5 pg/ml at baseline to 177 pg/ml at wk 1 (P < 0.001) with levels correlating with both serum phosphate (R = -0.74; P <0.05) and 1,25(OH)(2)D (R = -0.71; P < 0.05).

CONCLUSION:

Parenteral iron suppresses renal tubular phosphate reabsorption and 1alpha-hydroxylation of vitamin D resulting in hypophosphatemia. Our data suggest that this is mediated by an increase in FGF23.

PMID:
19366850
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Write to the Help Desk