title: Parathyroid hormone-related peptide, measured by a midmolecule radioimmunoassay, in various hypercalcaemic and normocalcaemic conditions.
abstract: The diagnosis of humoral hypercalcaemia of malignancy often presents considerable clinical problems. We have studied parathyroid hormone-related peptide (PTHrP) in serum from patients with humoral hypercalcaemia of malignancy (N = 22), hypercalcaemia of malignancy with skeletal metastases (17), histologically confirmed primary hyperparathyroidism (21) and hypercalcaemic patients with various benign diseases (9). PTHrP measurements were also made in normocalcaemic patients with various malignancies (23), endocrine diseases (13), sarcoidosis (22) and chronic renal failure (17). PTHrP was measured by a novel radioimmunoassay using rabbit antibodies directed towards the midregion of the molecule. Immuno- or silica cartridge extraction of serum before radioimmunoassay enabled us to measure PTHrP in all samples, which may add further information about circulating forms of PTHrP. PTHrP was clearly elevated in patients with humoral hypercalcaemia of malignancy (5.0 +/- 4.7 pmol/l) (mean +/- SD, N = 12) and when the kidney function was impaired (4.0 +/- 0.9 pmol/l) (N = 15) (silica cartridge extraction), whether the subject was hypercalcaemic or not. Some patients with endocrine diseases, including two with primary hyperparathyroidism, had slightly elevated serum PTHrP concentrations, while they were normal in sarcoidosis. In healthy subjects the levels were 1.1 +/- 0.5 pmol/l (N = 15) after immunoextraction and 0.8 +/- 0.2 pmol/l (N = 33) after silica cartridge extraction.
authors.affiliation: Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Bucht
authors.forename: A
authors.initials: A
authors.lastname: Eklund
authors.forename: G
authors.initials: G
authors.lastname: Toss
authors.forename: R
authors.initials: R
authors.lastname: Lewensohn
authors.forename: B
authors.initials: B
authors.lastname: Granberg
authors.forename: U
authors.initials: U
authors.lastname: Sjöstedt
authors.forename: R
authors.initials: R
authors.lastname: Eddeland
authors.forename: O
authors.initials: O
authors.lastname: Tørring
mesh_terms: D000368:Aged; D002118:Calcium / Q000097:blood*; D002846:Chromatography, Affinity; D004700:Endocrine System Diseases / Q000097:blood*; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000209:etiology; D008297:Male; D008722:Methods; D009369:Neoplasms / Q000097:blood* / Q000150:complications; D010281:Parathyroid Hormone / Q000032:analysis; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments / Q000097:blood*; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values
chemical_list: C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D011506:Proteins; D002118:Calcium