Short-Term Effects of Temperature and Thyrotropin-Releasing Hormone Stimulation on Adrenocorticotropin Stability in Horses.
Abstract: Pituitary pars intermedia dysfunction (PPID) is diagnosed by increased basal or post thyrotropin-releasing hormone (TRH) stimulation ACTH concentrations. ACTH is known to be unstable; however, the effect of different temperatures and TRH stimulation on equine ACTH stability is poorly described. In total, 15 horses, including 8 PPID positive (ACTH > 35 pg/mL at baseline or >65 pg/mL 30 min after TRH stimulation), were divided into 2 groups: 9, including 5 PPID positive, with basal ACTH concentrations and 6, including 3 PPID positive, with post TRH stimulation ACTH concentrations. Whole blood was stored for 1 h at 4, 20, 30, 40, or 70 °C. After centrifugation, immunoreactive ACTH concentrations were determined using a chemiluminescent assay. Linear mixed effect models were used to detect the effects of temperature, PPID status, and TRH stimulation on the immunoreactive ACTH concentration. Temperature had a significant effect ( = 0.003) on immunoreactive ACTH concentrations, and this effect was greater in PPID-negative horses ( = 0.01), with the changes in immunoreactive ACTH concentrations being slightly unpredictably higher or lower than samples stored at 4 °C. Even at 20 °C, mean immunoreactive ACTH concentrations minimally changed by 5% in PPID horses and 12% in non-PPID horses after 1 h. No significant effect of TRH stimulation was identified. Although ACTH concentrations should ideally be determined from samples kept at 4 °C, samples inadvertently left at temperatures of up to 40 °C can provide valid results if analyzed within 1 h; however, this increases the risks of altered ACTH concentrations, occasionally influencing the diagnosis of PPID.
Publication Date: 2022-01-28 PubMed ID: 35158648PubMed Central: PMC8833476DOI: 10.3390/ani12030324Google Scholar: Lookup
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- Journal Article
- Adrenocorticotropic Hormone (ACTH)
- Animal Health
- Animal Studies
- Chemiluminescent Assay
- Clinical Study
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Endocrine System
- Epidemiology
- Equine Science
- Hormones
- Horses
- Mathematical Model
- Physiology
- Pituitary Pars Intermedia Dysfunction
- Temperature
- Thyrotropin-Releasing Hormone
- Veterinary Medicine
- Veterinary Research
Summary
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The research investigates how different storage temperatures and thyrotropin-releasing hormone (TRH) stimulation impact the stability of Adrenocorticotropin (ACTH) hormone in horses, useful for diagnosing pituitary pars intermedia dysfunction (PPID). Conclusions emphasize the importance of maintaining blood samples at 4°C for reliable ACTH concentrations, although higher temperatures are deemed tolerable if analysis occurs within 60 minutes.
Objective and Methodology
- The study aimed to explore how changing storage temperatures and TRH stimulation affect the stability of the ACTH hormone in horses, a crucial factor in diagnosing PPID.
- The researchers worked with 15 horses; eight were determined PPID-positive, meaning they exhibited increased basal or post-TRH stimulation ACTH concentrations.
- These horses were split into two groups: one group had nine horses with basal ACTH concentrations, including five PPID positive, while the other group had six horses, including three PPID positive, with post TRH stimulation ACTH concentrations.
- The horse’s whole blood was stored at five different temperatures – 4°C, 20°C, 30°C, 40°C, and 70°C – for one hour before undergoing a chemiluminescent assay to determine immunoreactive ACTH concentrations.
- A statistical model – linear mixed effect – was used to identify potential effects of temperature, PPID status, and TRH stimulation on the concentration of ACTH in its immunoreactive form.
Findings and Conclusions
- Temperature proved to have a significant effect on immunoreactive ACTH concentrations, and this effect was more pronounced in PPID-negative horses.
- Even a minor increase to 20°C led to 5% change in ACTH concentrations in PPID horses and 12% in non-PPID horses after one hour.
- No detectable effect from TRH stimulation was found on ACTH concentrations.
- The researchers concluded that, for optimal ACTH concentration results, samples should ideally be kept at 4°C. However, results could still be considered valid if stored at temperatures up to 40°C, as long as analysis is undertaken within the hour.
- The study highlights potential risks for altered ACTH concentrations resulting from temperature discrepancies, which could influence diagnostic accuracy for PPID.
Cite This Article
APA
Hinrichsen SL, Yuen KY, Dryburgh EL, Bertin FR, Stewart AJ.
(2022).
Short-Term Effects of Temperature and Thyrotropin-Releasing Hormone Stimulation on Adrenocorticotropin Stability in Horses.
Animals (Basel), 12(3), 324.
https://doi.org/10.3390/ani12030324 Publication
Researcher Affiliations
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia.
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia.
- Boehringer Ingelheim Animal Health Australia Pty. Ltd., North Ryde, NSW 2113, Australia.
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia.
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia.
Grant Funding
- 1 / CSRD VA
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 4 times.- Kirkwood NC, Hughes KJ, Stewart AJ. Prospective Case Series of Clinical Signs and Adrenocorticotrophin (ACTH) Concentrations in Seven Horses Transitioning to Pituitary Pars Intermedia Dysfunction (PPID). Vet Sci 2022 Oct 17;9(10).
- Kirkwood NC, Hughes KJ, Stewart AJ. Pituitary Pars Intermedia Dysfunction (PPID) in Horses. Vet Sci 2022 Oct 10;9(10).
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