Rapid calcitonin response to experimental hypercalcemia in healthy horses.
Abstract: Calcium has important physiological functions, and disorders of calcium homeostasis are frequent in horses. We have made important progress understanding equine calcium homeostasis; however, limited information on equine calcitonin (CT) is available, in part because of the lack of validated CT assays. To determine the CT response to high ionized calcium (Ca(2+)) concentrations in healthy horses, we induced hypercalcemia in 10 healthy horses using a calcium gluconate 23% solution (5mg/kg; 120 mL/500 kg horse) infused over 4 min. Four horses were infused with 120 mL of 0.9% NaCl and used as controls. We validated a human-specific CT radioimmunoassay for use in horses. Serum Ca(2+) concentrations increased from 6.2+/-0.3mg/dL to 9.9+/-0.5mg/dL (4 min; P<0.01). Serum CT increased from 16.7+/-8.0 pg/mL to 87.1+/-55.8 pg/mL at 2 min, and 102.5+/-51.1 pg/mL at 4 min (P<0.01). Serum CT returned to baseline by 20 min, whereas serum Ca(2+) returned to baseline by 40 min. Of interest, CT concentrations returned to baseline despite hypercalcemia, suggesting thyroid gland C-cell CT depletion. Resting CT values higher than 40 pg/mL were considered abnormally elevated. No significant changes in serum Ca(2+) or CT concentrations were found in control horses. The coefficients of variation for the CT radioimmunoassay were lower than 11.9%. We conclude that the equine thyroid gland C-cell responds quickly to changes in extracellular Ca(2+) concentrations by secreting large quantities of CT into the systemic circulation, indicating that CT is important in equine calcium homeostasis. The human CT radioimmunoassay can be used to measure changes in equine CT.
Publication Date: 2008-12-27 PubMed ID: 19135828DOI: 10.1016/j.domaniend.2008.11.004Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Validation Study
Summary
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This research article investigates how a horse’s thyroid gland responds to higher concentrations of calcium by secreting calcitonin (CT), a hormone that regulates calcium levels in the body. The study, using a human-specific test, confirmed the quick reaction of horses’ thyroid C-cells to calcium changes and concluded that calcitonin plays a significant role in maintaining calcium balance in horses.
Research Methodology
- The study involved intentionally inducing hypercalcemia (an excess of calcium in the bloodstream) in ten healthy horses. This was achieved by administering a 23% calcium gluconate solution via an infusion.
- Four horses were used as controls, which were given an infusion of 0.9% NaCl (table salt) instead.
- The researchers took serum samples from the horses at regular intervals, testing for calcium and CT concentrations using a human-specific CT radioimmunoassay that was adapted and validated for horses.
Results and Findings
- They found that serum calcium levels significantly increased after the calcium gluconate infusion, and correspondingly, serum CT also increased.
- However, the levels of CT in the horses’ blood returned to their original levels rather quickly, within 20 minutes, despite calcium levels remaining high. This occurred faster than the calcium, which returned to baseline by 40 minutes.
- To the researchers, this suggested the rapid secretion and subsequent depletion of CT from the horses’ thyroid C-cell, as a response to the artificially induced hypercalcemia.
Conclusion
- The results led researchers to conclude that the horse’s thyroid gland C-cell rapidly responds to changes in calcium concentrations, thus highlighting the importance of CT in maintaining calcium balance in horses.
- They also found that resting CT values above 40 pg/mL were considered abnormally high. They suggested that the human CT radioimmunoassay can be used to measure changes in equine CT, providing a reliable method for future investigations into equine calcium homeostasis.
Cite This Article
APA
Rourke KM, Kohn CW, Levine AL, Rosol TJ, Toribio RE.
(2008).
Rapid calcitonin response to experimental hypercalcemia in healthy horses.
Domest Anim Endocrinol, 36(4), 197-201.
https://doi.org/10.1016/j.domaniend.2008.11.004 Publication
Researcher Affiliations
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon Tharp Street, Columbus, OH 43210, USA.
MeSH Terms
- Animals
- Calcitonin / blood
- Calcium / blood
- Horse Diseases / blood
- Horses / blood
- Hypercalcemia / blood
- Hypercalcemia / veterinary
- Radioimmunoassay / veterinary
- Reference Values
Citations
This article has been cited 4 times.- Fielding CL, Deane EL, Major DS, Mayer JR, Love JC, Peralez MS, Magdesian KG. Effects of calcium supplementation to resuscitation fluids in endurance horses: A randomized, blinded, clinical trial. J Vet Intern Med 2023 May-Jun;37(3):1216-1222.
- van den Broek DHN, Geddes RF, Williams TL, Chang YM, Elliott J, Jepson RE. Calcitonin Response to Naturally Occurring Ionized Hypercalcemia in Cats with Chronic Kidney Disease. J Vet Intern Med 2018 Mar;32(2):727-735.
- Felsenfeld AJ, Levine BS. Calcitonin, the forgotten hormone: does it deserve to be forgotten?. Clin Kidney J 2015 Apr;8(2):180-7.
- Conrad MB, Leatherwood JL, Paris BL, George JM, Martinez RE, Vergara-Hernandez FB, Nielsen BD, Colbath AC, Arnold CE, Glass KG, Welsh TH Jr, Bradbery AN. Effects of clodronate disodium on endocrine regulators of calcium in yearling horses. J Anim Sci 2025 Jan 4;103.
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