title: Circulating PTH and PTHrP levels before and after treatment of tumor induced hypercalcemia with Pamidronate Disodium (APD).
abstract: The effect of lowering ionized calcium on circulating parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) was assessed in twenty patients with hypercalcemia of malignancy following treatment with Pamidronate Disodium. Ionized calcium levels fell rapidly in all treated patients. PTH concentrations were initially suppressed below normal in 18 patients, but rose from 0.48 +/- 0.42 pmol/L to 3.63 +/- 3.13 pmol/L (p less than 0.01) after treatment, reaching higher than normal values in some patients even in the presence of persistent hypercalcemia. PTHrP concentrations did not change significantly after treatment. These findings are consistent with an increased sensitivity of parathyroid tissue to changes in ionized calcium following prolonged exposure to hypercalcemia. Regulation of tumor secretion of PTHrP by calcium was not apparent within the range of calcium concentrations in this study.
authors.affiliation: St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.
authors.forename: V
authors.initials: V
authors.lastname: Grill
authors.forename: R M
authors.initials: RM
authors.lastname: Murray
authors.forename: P W
authors.initials: PW
authors.lastname: Ho
authors.forename: J D
authors.initials: JD
authors.lastname: Santamaria
authors.forename: P
authors.initials: P
authors.lastname: Pitt
authors.forename: C
authors.initials: C
authors.lastname: Potts
authors.forename: G
authors.initials: G
authors.lastname: Jerums
authors.forename: T J
authors.initials: TJ
authors.lastname: Martin
mesh_terms: D002118:Calcium / Q000097:blood*; D004164:Diphosphonates / Q000627:therapeutic use*; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000188:drug therapy / Q000209:etiology; D009363:Neoplasm Proteins / Q000097:blood*; D009369:Neoplasms / Q000097:blood / Q000503:physiopathology*; D000077268:Pamidronate; D010281:Parathyroid Hormone / Q000097:blood*; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins / Q000378:metabolism*; D013997:Time Factors
chemical_list: D004164:Diphosphonates; D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D000077268:Pamidronate; D002118:Calcium