The Effects of Androstenone on the Plasma Serotonin, β-Endorphin, and Cortisol Concentrations in Thoroughbred Horses.
Authors: Choi Yeonju, Yoon Minjung
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Androstenone, a naturally occurring pheromone-like compound, has previously been shown to improve compliance in horses, though the neurochemical mechanisms underlying this behavioural shift remained unclear. Choi and Yoon investigated plasma concentrations of serotonin (5-HT), β-endorphin, and cortisol in eight thoroughbred horses following intranasal androstenone application (10 µg/mL in jojoba oil vehicle), measuring neuroendocrine responses at baseline, 15, 30, and 60 minutes post-treatment via ELISA. The androstenone-treated group maintained stable serotonin and β-endorphin levels throughout the observation period, whereas the control group exhibited significant time-dependent decreases in serotonin and paradoxical increases in β-endorphin; cortisol concentrations remained unchanged in both groups. These findings suggest androstenone may modulate emotional state and stress resilience through stabilisation of serotonergic and opioid pathways rather than via the hypothalamic-pituitary-adrenal axis, potentially explaining improved handling compliance. For practitioners, this implies androstenone treatment could represent a non-invasive, non-pharmacological approach to managing anxiety-related behaviours during stressful procedures, though wider validation across different horse populations, dosing protocols, and behavioural outcome measures would be necessary before routine clinical application.
Read the full abstract on PubMed
Practical Takeaways
- •Androstenone treatment may enhance compliance through neuroendocrine mechanisms involving serotonin and endorphin regulation, potentially useful for handling difficult horses
- •The effects on serotonin and endorphin suggest behavioral rather than stress-related mechanisms, since cortisol (stress marker) was unaffected
- •Further research needed with larger sample sizes and longer observation periods before recommending androstenone as a behavioral management tool in practice
Key Findings
- •Androstenone treatment maintained stable plasma serotonin (5-HT) concentrations while control group showed significant decrease over 60 minutes
- •Androstenone treatment maintained constant β-endorphin levels whereas control group showed increased concentration
- •Cortisol levels remained unchanged in both androstenone-treated and control groups across all time points
- •Androstenone appears to modulate serotonin and β-endorphin secretion, potentially explaining previously observed increases in horse compliance