Evaluation of serum parathyroid hormone-related peptide in hyperthyroid patients.
BACKGROUND
Hypercalcemia occurs in 10-20% of patients with hyperthyroidism, but its pathogenesis is still unclear.


OBJECTIVE
To evaluate changes in parathyroid hormone-related peptide (PTH-rP) concentration in hyperthyroid patients compared with healthy controls.


METHODS
We studied PTH-rP, parathormone (PTH) and ionized calcium levels in 153 hyperthyroid patients, and 89 control subjects. These variables were revaluated after attainment of euthyroidism with the antithyroid drug carbimazole for 6 months in a subgroup of 47 patients.


RESULTS
Pretreatment PTH-rP and ionized calcium level were significantly higher in hyperthyroid patients than in controls, whereas an opposite trend occurred for PTH. All parameters normalized after carbimazole therapy.


CONCLUSIONS
Untreated hyperthyroid patients exhibited a significant elevation in serum ionized calcium and PTH-rP and a significant reduction in serum PTH levels when compared with healthy controls. Our data favoured the hypothesis of a direct involvement of PTH-rP in the pathogenesis of hypercalcemia in hyperthyroid patients.
Giovanella
Luca
L
Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland. luca.giovanella@eoc.ch
Suriano
Sergio
S
Keller
Franco
F
Borretta
Giorgio
G
Ceriani
Luca
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D013956:Antithyroid Agents / Q000627:therapeutic use*; D002231:Carbimazole / Q000627:therapeutic use*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000378:metabolism* / Q000627:therapeutic use; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism*; D016896:Treatment Outcome; D055815:Young Adult
D013956:Antithyroid Agents; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D002231:Carbimazole