Fibroblast growth factor (FGF)-23 in patients with primary hyperparathyroidism.
OBJECTIVE
We aimed to determine the serum level of fibroblast growth factor-23 (FGF-23) in patients with primary hyperparathyroidism (pHPT) to understand its physiological role in the disorder.


METHODS
Ninety-eight patients with pHPT who underwent parathyroidectomy formed the study group. We also measured serum FGF-23 in 11 of these patients on postoperative day 6.


RESULTS
Serum FGF-23 levels was significantly higher in pHPT patients than in healthy controls (35.6+/-17.8 ng/l vs 28.9+/-11.2 ng/l (mean+/-s.d.); P<0.001 (Pearson's correlation coefficient)), but there was no significant difference in the serum FGF-23 level between pHPT patients with normal renal function (creatinine clearance (Ccr) of >or=70 ml/min) and healthy controls. Serum FGF-23 correlated positively with serum calcium (P<0.0001) and intact parathyroid hormone (PTH) (P<0.01), and negatively with Ccr (P<0.001), serum phosphate (P<0.05), and serum 1,25-dihydroxyvitamin D (1,25(OH)(2)D) (P<0.05). Multiple linear regression analysis of factors potentially determining serum FGF-23 levels in pHPT patients showed serum calcium (P<0.01) and Ccr (P<0.001) to be significant predictors. The serum levels of FGF-23 did not change after parathyroidectomy despite the normalization of serum calcium values. Multiple linear regression analysis revealed that serum FGF-23 was not a significant predictor of serum phosphate or 1,25(OH)(2)D in pHPT patients.


CONCLUSIONS
FGF-23 may not play a significant role in regulating phosphate or 1,25(OH)(2)D in pHPT patients, especially in those with normal renal function. Further studies are warranted to determine the role of FGF-23 in renal insufficiency or failure.
Yamashita
Hiroyuki
H
Noguchi Thyroid Clinic and Hospital Foundation, Oita, Japan. yama@noguchi-med.or.jp
Yamashita
Takeyoshi
T
Miyamoto
Masashi
M
Shigematsu
Takashi
T
Kazama
Junichiro James
JJ
Shimada
Takashi
T
Yamazaki
Yuji
Y
Fukumoto
Seiji
S
Fukagaw
Masafumi
M
Noguchi
Shiro
S
D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000097:blood; D051437:Renal Insufficiency / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
C000717427:FGF23 protein, human; D010710:Phosphates; D014807:Vitamin D; D005346:Fibroblast Growth Factors; C097949:1,25-dihydroxyvitamin D; D000089703:Fibroblast Growth Factor-23; D002118:Calcium