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Home / Equine Research Bank / J Vet Intern Med / The effect of freeze-thaw cycles on determination of immunor...
Journal of veterinary internal medicine2020; 34(3); 1350-1356; doi: 10.1111/jvim.15771

The effect of freeze-thaw cycles on determination of immunoreactive plasma adrenocorticotrophic hormone concentrations in horses.

Abstract: Determination of plasma adrenocotrophic hormone (ACTH) concentration (endogenous or thyrotropin-releasing hormone [TRH] stimulation test) is the most commonly used diagnostic test for pituitary pars intermedia dysfunction (PPID) in horses. Because ACTH is unstable, samples often are frozen to be shipped to laboratories or to allow for batch analysis of research samples. However, the effect of multiple freeze-thaw cycles on equine ACTH is unknown. Objective: To determine the effects of multiple freeze-thaw cycles on immunoreactive ACTH concentration. Methods: Twenty-eight horses ranging from 10 to 27 years of age were used. Methods: Prospective study. Horses were divided into 4 groups: group 1, PPID-negative, without TRH stimulation; group 2, PPID-negative, with TRH stimulation; group 3, PPID-positive, without TRH stimulation; and group 4, PPID-positive, with TRH stimulation. Whole blood was collected from each horse at baseline or 30 minutes after TRH stimulation. Immunoreactive plasma ACTH concentration was determined using a chemiluminescence assay. Plasma samples then were frozen at -80°C >24 hours, thawed at 4°C and reanalyzed for 5 freeze-thaw cycles. Changes in plasma ACTH concentration were analyzed using a linear mixed-effect model. Results: Significant effects of freeze-thaw cycles (P = .001) and PPID status (P = .04) on plasma ACTH concentration were observed, but no significant effect of TRH stimulation was identified. Conclusions: The plasma ACTH concentration is altered by freeze-thaw cycles, and the effect is observed sooner in horses with PPID. To diagnose PPID, multiple freeze-thaw cycles should be avoided when measuring plasma ACTH concentration.
© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
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Publication Date: 2020-04-07 PubMed ID: 32255541PubMed Central: PMC7255672DOI: 10.1111/jvim.15771Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article explores how freeze-thaw cycles impact the determination of immunoreactive plasma adrenocorticotrophic hormone (ACTH) concentrations in horses, specifically those with pituitary pars intermedia dysfunction (PPID). The researchers found that the freeze-thaw process impacts ACTH concentration and noticed the changes sooner in horses with PPID.

Objective and Methods

  • The objective of the research was to pinpoint the effects of multiple freeze-thaw cycles on immunoreactive ACTH concentration. This hormone is often assessed to diagnose PPID in horses.
  • 28 horses were involved in the prospective study, with ages ranging from 10 to 27 years. They were divided into four groups based on their PPID status and whether thyrotropin-releasing hormone (TRH) stimulation had been performed.
  • The scientists gathered whole blood from each horse, either at baseline or 30 minutes post-TRH stimulation.
  • They determined the immunoreactive plasma ACTH concentration via a chemiluminescence assay. The plasma samples were subsequently frozen at -80°C for over 24 hours, then thawed at 4°C and reanalyzed across five freeze-thaw cycles.

Findings and Conclusion

  • The analysis demonstrated significant effects from freeze-thaw cycles (P = .001) and PPID status (P = .04) on the concentration of plasma ACTH. TRH stimulation, however, had no significant impact.
  • It was concluded that the plasma ACTH concentration is influenced by freeze-thaw cycles, and this effect is noticed more rapidly in horses with PPID.
  • The researchers suggest refraining from multiple freeze-thaw cycles when attempting to measure plasma ACTH concentration for diagnosing PPID.

Overall Implication

  • This study has important implications for the veterinary and research fields. It underlines the necessity of sample handling, specifically how the freeze-thaw process can alter the diagnostic variables such as ACTH concentration.

Cite This Article

APA
Hu K, Stewart AJ, Yuen KY, Hinrichsen S, Dryburgh EL, Bertin FR. (2020). The effect of freeze-thaw cycles on determination of immunoreactive plasma adrenocorticotrophic hormone concentrations in horses. J Vet Intern Med, 34(3), 1350-1356. https://doi.org/10.1111/jvim.15771

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 34
Issue: 3
Pages: 1350-1356

Researcher Affiliations

Hu, Ke
  • School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Stewart, Allison J
  • School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Yuen, Ka Y
  • School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Hinrichsen, Sophia
  • School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Dryburgh, Elizabeth L
  • Boehringer Ingelheim Pty Ltd, North Ryde, New South Wales, Australia.
Bertin, François-René
  • School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.

MeSH Terms

  • Adrenocorticotropic Hormone / blood
  • Animals
  • Diagnostic Tests, Routine
  • Female
  • Freezing / adverse effects
  • Horse Diseases / blood
  • Horse Diseases / diagnosis
  • Horses
  • Luminescent Measurements / veterinary
  • Male
  • Pituitary Diseases / blood
  • Pituitary Diseases / diagnosis
  • Pituitary Diseases / veterinary
  • Prospective Studies
  • Specimen Handling / methods
  • Specimen Handling / veterinary
  • Thyrotropin-Releasing Hormone / administration & dosage

Grant Funding

  • Boehringer-Ingelheim Pty Ltd
  • Master of Veterinary Science research project sche / School of Veterinary Science, The University of Queensland

Conflict of Interest Statement

Elizabeth L. Dryburgh is employed by Boehringer‐Ingelheim Pty Ltd, and Allison J. Stewart and François‐René Bertin have consulted for Boehringer‐Ingelheim Pty Ltd.

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Citations

This article has been cited 11 times.
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