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Equine veterinary journal2025; doi: 10.1111/evj.14468

Effect of pergolide treatment on insulin dysregulation in horses and ponies with pituitary pars intermedia dysfunction.

Abstract: Due to the high frequency of laminitis reported for both conditions, the relationship between pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID), and the potential role of dopamine in modifying insulin secretion, requires further investigation. Objective: To evaluate the effect of pergolide mesylate on insulin sensitivity and postprandial insulin and glucose responses in horses and ponies with ID, both with or without concurrent PPID. Methods: Randomised crossover study. Methods: Sixteen horses and ponies, comprising eight matched pairs (PPID+ID or ID-only), were given pergolide mesylate at a dose of 2 μg/kg bwt orally once daily for 4 weeks (plus a 4-week non-treatment control period, with a 4-week washout between phases). A combined glucose and insulin tolerance test (CGIT) and a standard meal test (SMT; containing 1.1 g/kg bwt of starch and 0.1 g/kg bwt of free sugars), were performed before and after each treatment period to determine insulin sensitivity and postprandial insulin and glucose responses, respectively. Variables derived from the CGIT and SMT were analysed using linear mixed models. Results: Pergolide treatment did not alter any of the variables derived from the CGIT in either the PPID+ID or ID-only groups (all p > 0.05). For the SMT, insulin responses were reduced by pergolide treatment for the PPID+ID group, with Δ change values for the total area under the curve for insulin over 300 mins (estimated marginal mean [95% confidence interval]) being -25.4 (-39.9 to -7.3) min∙mIU/mL (p = 0.03) and Δ change values for peak insulin concentration being -100 (-167 to -29) μIU/mL (p = 0.04). No effect of pergolide treatment was detected for the ID-only group. Conclusions: Number of animals and heterogeneity among groups. Conclusions: Pergolide had no effect on tissue insulin sensitivity. However, the results suggest that postprandial hyperinsulinaemia may be limited by this dopamine receptor agonist in animals with PPID plus ID.
© 2025 Boehringer Ingelheim, Mars Horsecare and The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2025-02-18 PubMed ID: 39967360DOI: 10.1111/evj.14468Google Scholar: Lookup
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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 focuses on understanding the effect of pergolide on insulin sensitivity and insulin and glucose responses in horses and ponies with insulin dysregulation (ID) and those with insulin dysregulation and concurrent pituitary pars intermedia dysfunction (PPID+ID). The study concluded that pergolide does not change insulin sensitivity, but it seems to moderate post-meal hyperinsulinemia in animals with both PPID and ID.

Research Methodology

  • Horses and ponies, selected for the study, were divided into matched pairs based on those who had PPID with insulin dysregulation or just insulin dysregulation.
  • The animals were administered pergolide mesylate, a dopamine receptor agonist, orally once daily for four weeks. They also went through a four-week period without treatment and four-week washout between phases.
  • Insulin sensitivity and post-meal insulin and glucose responses were determined using a combined glucose and insulin tolerance test (CGIT) and a standard meal test (SMT).
  • Results from these tests were analyzed using linear mixed models.

Results and Conclusion

  • No observed changes in any of the variables drawn from the CGIT in both the PPID+ID group and the ID-only group.
  • However, for the SMT, it was noted that the pergolide treatment reduced insulin responses in the PPID+ID group.
  • These insulin responses after the treatment were quantified with Δ change values for the total insulin area under the curve over 300 mins and peak insulin concentration.
  • No effects of pergolide treatment were seen in the ID-only group.
  • Despite the treatment’s lack of effect on tissue insulin sensitivity, the study suggests that pergolide may limit postprandial hyperinsulinemia (high insulin levels after a meal) in animals with both PPID and ID.

This research offers valuable insights into the role of pergolide on insulin regulation in animals with ID, with or without concurrent PPID, and could lay the groundwork for further examination in the treatment of these conditions using dopamine receptor agonists.

Cite This Article

APA
Galinelli NC, Bamford NJ, Erdody ML, Mackenzie SA, Warnken T, Harris PA, Sillence MN, Bailey SR. (2025). Effect of pergolide treatment on insulin dysregulation in horses and ponies with pituitary pars intermedia dysfunction. Equine Vet J. https://doi.org/10.1111/evj.14468

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Galinelli, Nicolas C
  • Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
Bamford, Nicholas J
  • Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
Erdody, Madison L
  • Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
Mackenzie, Skye A
  • Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
Warnken, Tobias
  • Boehringer Ingelheim Vetmedica GmbH, Ingelheim am Rhein, Germany.
Harris, Patricia A
  • Equine Studies Group, Waltham Petcare Science Institute, Melton Mowbray, UK.
Sillence, Martin N
  • School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia.
Bailey, Simon R
  • Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.

Grant Funding

  • LP180101000 / Australian Research Council
  • Boehringer Ingelheim
  • Waltham Centre for Pet Nutrition

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