Biological potency and radioimmunoassay of canine calcitonin

Hazewinkel, H. A. W., Schoenmakers, I., Pelling, D., Snijdelaar, M., Wolfswinkel, J. and Mol, J. A. (1999) Biological potency and radioimmunoassay of canine calcitonin. Domestic Animal Endocrinology, 17 (4). pp. 333-344. ISSN 0739-7240

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Abstract

Calcitonin (CT) is a major calcitropic hormone. Because of low cross reactivity of canine CT (cCT) in radioimmunoassays (RIA) developed for other species, a homologous RIA is needed. Synthesis of cCT allowed study of its biologic potency using a rat bioassay and its plasma half-life in dogs. The availability of cCT also made possible the development of a homologous RIA for measurement of basal and stimulated plasma CT concentrations in dogs. The biologic potency of the synthesized cCT in rats is 24 IU/mg of peptide, which is low in comparison with the 4,000 IU/mg of the salmon CT standard. In the dog, an even lower potency of 4.4 IU/mg of cCT was found. Measurement of the disappearance of iv-injected radioiodinated or nonradioiodinated cCT revealed a short biologic half-life of less than 3 min, followed by a long half-life of 20 min. A polyclonal antiserum against synthetic cCT was raised in a goat. Using a final antiserum dilution of 1:12,000 and 125I-labeled synthetic cCT, the RIA had a detection limit of 6.5 ng/l. The antibody did not crossreact with standard human CT and had <0.1% cross reactivity with porcine CT. For measurement of plasma cCT concentrations, an extraction procedure was developed using ethanol. Dilutions of synthetic cCT and canine plasma extracts revealed parallelism over a wide range of concentrations. Size exclusion chromatography of canine plasma extracts on Biogel P-10 revealed a single cCT peak at the same position as [125I]-cCT, showing that there was little interference by other proteins or cCT prohormone. Basal plasma CT concentrations were 12–80 ng/l, and there was an 8- and 20-fold increase after calcium (1 and 2.5 mg/kg body weight) bolus infusion.

Item Type:	Article
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Groups > Nutrition and Preventive Medicine Faculty of Medicine and Health Sciences > Research Groups > Musculoskeletal Medicine
Related URLs:	https://linkinghub.elsevier.com/retrieve...
Depositing User:	LivePure Connector
Date Deposited:	28 Jan 2022 12:34
Last Modified:	23 Oct 2022 03:29
URI:	https://ueaeprints.uea.ac.uk/id/eprint/83209
DOI:	10.1016/S0739-7240(99)00058-2

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