Increased adrenocortical response to adrenocorticotropic hormone (ACTH) in sport horses with equine glandular gastric disease (EGGD).

The study explores the relationship between adrenocortical function and equine gastric ulcer syndrome (EGUS) in sport horses. It finds a potential link, suggesting that horses with glandular gastric disease may have an increased adrenocortical reaction to ACTH stimuli.

Study Design and Objectives

• The researchers sought to investigate whether adrenocortical function is altered in horses with equine gastric ulcer syndrome (EGUS).
• Test subjects included 26 sport horses actively competing at national or international levels. 15 of the horses were classified under eventing, and 11 fell under endurance.
• To assess adrenocortical function, each horse underwent a gastroscopic examination and an adrenocorticotropic hormone (ACTH) stimulation test.

Methods and Findings

• Salivary cortisol concentrations were measured both before and after an intravenous ACTH injection. These measurements occurred at different time intervals, namely 30, 60, 90, 120, and 150 minutes after the injection.
• Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) are two separate diseases that fall under the umbrella of EGUS. The diagnoses revealed that ESGD was present in a significant percentage of horses, differing in prevalence between eventing and endurance horses; however, there was no correlation between its presence or severity with the presence or severity of EGGD.
• EGGD was significantly prevalent in both categories of horses, with a higher incidence in endurance as opposed to eventing horses.
• Notably, ACTH stimulation resulted in a larger increase in cortisol concentration in horses with moderate severity of EGGD compared to those with a mild form.

Conclusions and Implications

• Data indicated an increased adrenocortical response to ACTH stimulation in horses with glandular gastric disease, suggesting that EGGD could be associated with enhanced adrenocortical sensitivity.
• The findings call for further investigations to confirm the association between adrenocortical sensitivity and EGGD and to understand the pathophysiological mechanisms involved. Such studies could potentially shape ways to manage and treat EGUS in sport horses.