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Updated: Dec 30, 2025

Fecal Glucocorticoid Analysis: Non-invasive Adrenal Monitoring in Equids
Published on: April 25, 2016
Plasma steroid profiles before and after ACTH stimulation test in healthy horses
A Kirchmeier1, A E van Herwaarden2, J H van der Kolk1
1Department of Clinical Veterinary Medicine, Swiss Institute of Equine Medicine (ISME), Vetsuisse Faculty, University of Bern, and Agroscope, Länggassstrasse 124, 3012 Bern, Switzerland.
Abstract:
This study describes steroid profiles in equine plasma before and after ACTH stimulation. In human medicine, other steroids have been shown to have a more pronounced reaction to an ACTH stimulation test than cortisol. This study aimed to determine if the same was true for the horse. A total of 11 clinically healthy horses were selected for this study. Ethylenediaminetetraacetic acid plasma samples were taken before and 60 min after stimulation with 1 μg/kg BW of synthetic ACTH administered intravenously. The samples were analyzed for cortisol, 11-deoxycortisol, 21-deoxycortisol, cortisone, corticosterone, 11-deoxycorticosterone, androstenedione, 17-OH-progesterone, progesterone, and testosterone with a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cortisol, 11-deoxycortisol, cortisone, corticosterone, and 11-deoxycorticosterone showed a significant increase after ACTH stimulation. In conclusion, the LC-MS/MS represents a viable method to measure glucocorticoids and related precursors or metabolites in equine plasma samples. In addition, we were able to show a more pronounced increase of 11-deoxycorticosterone, 11-deoxycortisol, and corticosterone compared with cortisol. These 3 metabolites could potentially serve as more sensitive biomarkers for stress in horses than cortisol.
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