title: Clinical applicability of an amino-terminal radioimmunoassay for determination of parathyroid hormone.
abstract: With a radioimmunoassay using hPTH 1-34 for antibody production, for radioiodination and as a standard, hPTH 1-34 was detectable (detection limit 40 pg/ml) preoperatively in peripheral blood in 14 of 29 patients with hyperparathyroidism, but in no controls. In all patients with parathyroid adenoma and detectable hPTH 1-34 preoperatively, the values fell after parathyroid surgery. Contrastingly, three of four patients with diffuse parathyroid hyperplasia and two of three with normal parathyroid glands showed a rise in hPTH 1-34 postoperatively, which was concomitant with very low serum calcium levels. In studies of hPTH 1-34 in central venous blood (3 patients), levels were detectable in all samples, but not in simultaneously drawn peripheral blood. Values for hPTh 1-34 in central blood correlated to PTH determined from a bovine assay, but the peripheral samples showed no correlation. The low levels of circulating N-terminal immunoreactivity in peripheral blood make this assay inapplicable for routine diagnostic purposes. These low levels are due not only to low secretion rates, but also to rapid peripheral metabolization.
authors.affiliation: Department of Endocrine Surgery, Rigshospitalet, Copenhagen, Denmark.
authors.forename: C L
authors.initials: CL
authors.lastname: Mollerup
authors.forename: E
authors.initials: E
authors.lastname: Bruun
authors.forename: J
authors.initials: J
authors.lastname: Hesselfeldt-Nielsen
authors.forename: L
authors.initials: L
authors.lastname: Hummer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010443:Peptide Chain Termination, Translational; D011863:Radioimmunoassay / Q000379:methods*
chemical_list: D010281:Parathyroid Hormone