title: A rapid extraction method for serum calcitonin.
abstract: A rapid, simple and reliable extraction method for calcitonin from serum has been developed. 2 volumes of acidic ethanol and 1 volume of serum were mixed, centrifuged, and the supernatant was evaporated to dryness. The extracts were reconstituted in assay buffer before radioimmunoassay was performed. Basal concentrations of calcitonin after extraction were 5.4 +/- 3.0 pg-equivalents/ml (mean +/- SD), females, n = 48 and 8.8 +/- 5.5 pg-equivalents/ml, males, n = 42. Calcitonin was detectable in serum from all males and from 90% of the females. The concentrations in males were significantly higher (P less than 0.001). There was a more pronounced calcitonin response in males (n = 12) than in females (n = 12) to a calcium clamp (P less than 0.01). Gel chromatography of serum from patients with medullary thyroid carcinoma on a Sephadex G-75 column and a TSK G 2000 SW column in a fast protein liquid chromatography system, disclosed that the ethanol extraction excluded the high mol mass forms of calcitonin. We propose the acidic ethanol extraction as a convenient method for routine measurements of calcitonin.
authors.affiliation: Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Bucht
authors.forename: B
authors.initials: B
authors.lastname: Granberg
authors.forename: U
authors.initials: U
authors.lastname: Sjöstedt
authors.forename: O
authors.initials: O
authors.lastname: Tørring
mesh_terms: D002116:Calcitonin / Q000097:blood* / Q000302:isolation & purification; D002850:Chromatography, Gel; D000431:Ethanol / Q000494:pharmacology; D006801:Humans; D008722:Methods
chemical_list: D000431:Ethanol; D002116:Calcitonin