title: Evaluation of serum parathyroid hormone-related peptide in hyperthyroid patients.
abstract: 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.
authors.affiliation: Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland. luca.giovanella@eoc.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
authors.forename: Sergio
authors.initials: S
authors.lastname: Suriano
authors.forename: Franco
authors.initials: F
authors.lastname: Keller
authors.forename: Giorgio
authors.initials: G
authors.lastname: Borretta
authors.forename: Luca
authors.initials: L
authors.lastname: Ceriani
mesh_terms: 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
chemical_list: D013956:Antithyroid Agents; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D002231:Carbimazole