Determination of circulating monomeric katacalcin and calcitonin: physiological studies in normal subjects.

Abstract

Katacalcin is a recently discovered peptide, contained within the calcitonin precursor. For the highly sensitive radioimmunological measurement of katacalcin and calcitonin we used extraction on C-18, thereby lowering the detection limits in serum to 0.8 pmol/l (katacalcin) and 0.7 pmol/l (calcitonin), and simultaneously improving the specificities of both assays for the monomeric forms of the peptides. Extraction recoveries were greater than 96% and greater than 95% for pure monoiodinated [125I]Tyr(0)-katacalcin and [125I]calcitonin, respectively; and 95-98% and 91-97% respectively for the corresponding unlabelled peptides. This method is sufficiently sensitive and specific for studies on the physiology of both peptides. Gel filtration of serum from a patient with medullary carcinoma of the thyroid showed that the majority of high molecular weight forms of katacalcin and calcitonin did not bind to C-18, and that the eluted material consisted to more than 90% of monomeric katacalcin and calcitonin. Basal levels (mean +/- SEM) of katacalcin were higher in men (3.0 +/- 0.6 pmol/l, age less than 40 years, and 1.8 +/- 0.4 pmol/l, age greater than 40 years) and younger women (2.1 +/- 0.4 pmol/l) than in older women (1.3 +/- 0.6 pmol/l; p less than 0.02). The respective values for calcitonin were 5.1 +/- 0.9 and 4.0 +/- 0.6 pmol/l for young and older men, and 2.3 +/- 0.4 and 2.8 +/- 0.8 pmol/l for young and older women, with a significant sex-related difference in both age groups. Basal serum levels of katacalcin and calcitonin were highly correlated (katacalcin = 0.66 calcitonin -0.12 pmol/l; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

• Authors: W Woloszczuk, H Schuh, J Kovarik
• Journal: Journal of clinical chemistry and clinical biochemistry. Zeitschrift fur klinische Chemie und klinische Biochemie (J Clin Chem Clin Biochem) Vol. 24 Issue 7 Pg. 451-5 (Jul 1986) ISSN: 0340-076X [Print] Germany
• PMID: 3755463 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Peptide Fragments
• katacalcin
• Calcitonin
• Calcium

Topics

• Adolescent
• Adult
• Age Factors
• Aged
• Calcitonin (blood)
• Calcium
• Chromatography, Gel
• Female
• Humans
• Male
• Middle Aged
• Peptide Fragments (blood)
• Reference Values