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Home / Equine Research Bank / J Vet Intern Med / Variation in plasma adrenocorticotropic hormone concentratio...
Journal of veterinary internal medicine2005; 19(2); 217-222; doi: 10.1892/0891-6640(2005)19<217:vipahc>2.0.co;2

Variation in plasma adrenocorticotropic hormone concentration and dexamethasone suppression test results with season, age, and sex in healthy ponies and horses.

Abstract: The purpose of this study was to evaluate the variation in plasma adrenocorticotropic hormone (ACTH) concentration and dexamethasone suppression test (DST) results with season, age, and sex in healthy, pony mares (n=15) and pony stallions (n=14) living under semiferal conditions and horse mares (n=10) living at pasture. Plasma ACTH concentrations were measured in September 2002, and in January, May, and September 2003. DSTs were performed in January and September 2003. Plasma ACTH concentrations in September 2002 and September 2003 were similar and were significantly greater than in January and May (P .05). Seasonal changes in plasma ACTH concentration and DST results should be considered when interpreting endocrine test results.
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Publication Date: 2005-04-13 PubMed ID: 15822567DOI: 10.1892/0891-6640(2005)19<217:vipahc>2.0.co;2Google 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.

This research investigates how the level of adrenocorticotropic hormone (ACTH) in the blood, and the results of a dexamethasone suppression test (DST), vary with season, age, and sex in healthy ponies and horses.

Research Methodology and Subjects

  • The study evaluated the variations in ACTH concentration and DST results in a group of healthy mares (female ponies), stallions (male ponies), and horse mares.
  • The ponies were living under semiferal conditions, while the horses were kept at pasture.
  • ACTH levels in plasma were measured in September 2002, and then again in January, May, and September 2003.
  • Two DSTs were also performed in January and September 2003 to measure ACTH concentration response to dexamethasone, a type of steroid medication.

Results and Analysis

  • The ACTH concentrations in September of both years were found to be similar, and significantly higher than the measurements in January and May.
  • ACTH levels were within the reference range for nearly all subjects in January and May, but fell below the reference range for the majority in September.
  • DST results were found to be within the reference range for all subjects in January, and for around 74% of the subjects in September 2003.
  • A noticeable increase in plasma cortisol concentration was found at the end of the DST in September compared to January.
  • The study uncovered a positive correlation between age and ACTH and cortisol concentration at the beginning and end of the DST. This suggests that as the subjects age, their ACTH and cortisol levels increase.
  • No significant differences in ACTH concentration were found among horse mares, pony mares, and pony stallions when measurements were taken during the same season.

Conclusions and Implications

  • The research concludes that seasonal changes can impact plasma ACTH concentration and DST results significantly and therefore need to be taken into account when interpreting endocrine test results.
  • In particular, it suggests a pattern of significantly higher ACTH concentration in September compared to January and May, which could be a potential challenge while diagnosing and treating related endocrine disorders.

Cite This Article

APA
Donaldson MT, McDonnell SM, Schanbacher BJ, Lamb SV, McFarlane D, Beech J. (2005). Variation in plasma adrenocorticotropic hormone concentration and dexamethasone suppression test results with season, age, and sex in healthy ponies and horses. J Vet Intern Med, 19(2), 217-222. https://doi.org/10.1892/0891-6640(2005)19<217:vipahc>2.0.co;2

Publication

Journal of veterinary internal medicine
ISSN: 0891-6640
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 19
Issue: 2
Pages: 217-222

Researcher Affiliations

Donaldson, Mark T
  • Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA. mtd@vet.upenn.edu
McDonnell, Sue M
    Schanbacher, Barbara J
      Lamb, Stephen V
        McFarlane, Dianne
          Beech, Jill

            MeSH Terms

            • Adrenocorticotropic Hormone / blood
            • Aging / blood
            • Animals
            • Body Size
            • Cushing Syndrome / diagnosis
            • Cushing Syndrome / veterinary
            • Dexamethasone
            • Female
            • Horse Diseases / diagnosis
            • Horses / blood
            • Male
            • Seasons
            • Sex Factors

            Citations

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