Journal of veterinary internal medicine2011; 25(6); 1431-1438; doi: 10.1111/j.1939-1676.2011.00810.x

Comparison of cortisol and ACTH responses after administration of thyrotropin releasing hormone in normal horses and those with pituitary pars intermedia dysfunction.

Abstract: Changes in both adrenocorticotropin (ACTH) and cortisol concentration in response to thyrotropin releasing hormone (TRH) administration have been used to diagnose equine pituitary pars intermedia dysfunction (PPID), but the use of the 2 hormones has not been compared. Objective: Measuring ACTH concentration is superior to measuring cortisol concentration after TRH administration in differentiating between normal horses and those with PPID, and the 2 hormone concentrations are disassociated in PPID horses. Methods: Eleven horses and 2 ponies with PPID and 19 normal horses. Methods: A study evaluating cortisol and ACTH concentrations before and at 14, 30, and 60 minutes after TRH administration. Results: At 14 and 30 minutes after TRH administration, cortisol concentration increased in PPID horses, and ACTH increased in all groups; ACTH, but not cortisol concentration, was significantly higher in PPID horses compared with normal horses. A relationship between cortisol concentration and ACTH concentration was seen in normal horses, but not in horses with PPID. Compared with normal castrated males, normal female horses had a greater change in cortisol concentration per unit change of ACTH concentration. Conclusions: ACTH and cortisol concentrations are disassociated in horses with PPID. Measuring ACTH concentration after TRH administration appears superior to measuring cortisol concentration as a diagnostic test for PPID.
Publication Date: 2011-10-07 PubMed ID: 22092639DOI: 10.1111/j.1939-1676.2011.00810.xGoogle Scholar: Lookup
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  • Journal Article
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  • Non-U.S. Gov't

Summary

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The research investigates the effectiveness of measuring ACTH (adrenocorticotropin) concentration compared to cortisol concentration after TRH (thyrotropin releasing hormone) administration in identifying pituitary pars intermedia dysfunction (PPID) in horses. Results suggest that ACTH concentration is a better diagnostic indicator than cortisol concentration for PPID in horses.

Objective and Background

  • The study focuses on exploring the competencies of two hormones, adrenocorticotropin (ACTH) and cortisol, in diagnosing equine pituitary pars intermedia dysfunction (PPID), a common endocrine disorder in aged horses.
  • This disease can cause a range of clinical signs like abnormal hair growth, muscle wastage, and abnormal fat distribution.
  • Earlier studies have used the rise in cortisol and ACTH concentrations in response to administration of thyrotropin releasing hormone (TRH), a stimulating hormone, as a test for PPID. However, the two hormones haven’t been compared for their diagnostic efficacy.

Methods and Study Subjects

  • The research involved 11 horses and 2 ponies with PPID, and 19 normal horses.
  • The investigators compared the concentrations of cortisol and ACTH in these horses before the administration of TRH, and again at 14, 30, and 60 minutes after the TRH was given.

Results and Findings

  • Results from the study showed that both ACTH concentration and cortisol concentration went up in horses (including those with PPID) at 14 and 30 minutes after TRH administration.
  • However, only the ACTH concentration was significantly higher in PPID horses in comparison to the normal horses.
  • There seemed to be a correlation between ACTH and cortisol concentrations in normal horses, but not in horses with PPID.
  • The study also revealed that compared to castrated male counterparts, normal female horses showed a greater change in cortisol concentration per unit change of ACTH concentration.

Conclusions

  • The study concludes that ACTH concentration appears to be superior to cortisol concentration as an indicator after TRH administration for diagnosing PPID in horses.
  • Furthermore, the data suggested a disassociation between ACTH and cortisol concentrations in horses diagnosed with PPID, differentiating them from normal horses.

Cite This Article

APA
Beech J, Boston R, Lindborg S. (2011). Comparison of cortisol and ACTH responses after administration of thyrotropin releasing hormone in normal horses and those with pituitary pars intermedia dysfunction. J Vet Intern Med, 25(6), 1431-1438. https://doi.org/10.1111/j.1939-1676.2011.00810.x

Publication

ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 25
Issue: 6
Pages: 1431-1438

Researcher Affiliations

Beech, J
  • Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, Kennett Square, PA 19348, USA. jbeech@vet.upenn.edu
Boston, R
    Lindborg, S

      MeSH Terms

      • Adrenocorticotropic Hormone / blood
      • Adrenocorticotropic Hormone / metabolism
      • Animals
      • Female
      • Horse Diseases / blood
      • Horse Diseases / metabolism
      • Horses
      • Hydrocortisone / blood
      • Hydrocortisone / metabolism
      • Male
      • Pituitary Diseases / blood
      • Pituitary Diseases / metabolism
      • Pituitary Diseases / veterinary
      • Pituitary Gland, Intermediate
      • Sex Characteristics
      • Thyrotropin-Releasing Hormone / administration & dosage
      • Thyrotropin-Releasing Hormone / pharmacology

      Citations

      This article has been cited 11 times.
      1. Drozdzewska K, Gehlen H. Markers for internal neoplasia in the horse.. Vet Med Sci 2023 Jan;9(1):132-143.
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      2. 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).
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        doi: 10.3390/ani10081426pubmed: 32824027google scholar: lookup
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      10. Diandong H, Feng G, Zaifu L, Helland T, Weixin F, Liping C. Sea buckthorn (Hippophae rhamnoides L.) oil protects against chronic stress-induced inhibitory function of natural killer cells in rats.. Int J Immunopathol Pharmacol 2016 Mar;29(1):76-83.
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