Quantification and comparison of baseline cortisol levels between aqueous and plasma from healthy anesthetized hound dogs utilizing mass spectrometry




The purpose of this study is to quantify and compare the resting cortisol levels between aqueous (Aq) and plasma of anesthetized hound dogs utilizing mass spectrometry.


Nine hound breed dogs weighing between 20.8 and 29.2 kg (math formula = 26.3 kg, SD ± 2.6 kg) were utilized from a previous project.


All dogs underwent two anesthesia sessions to harvest Aq from each eye respectively. A paired blood sample was taken immediately after aqueous centesis. The Aq and plasma were analyzed for cortisol levels using mass spectrometry. Correlation of cortisol levels in dog serum and ocular fluid was determined with Sigma Stat using Pearson's correlation analysis. The level of significance for correlation analysis was set at P < 0.05.


The plasma resting cortisol levels in the dog ranged from 3.59 to 89.35 nm (math formula = 31.68 nm, SD ± 28.53 nm), while the Aq cortisol levels ranged from 0.82 to 5.62 nm (math formula = 2.73 nm, SD ± 1.94 nm). The correlation of cortisol levels in Aq compared to plasma was significant (P = 0.008) with a correlation coefficient of r = 0.779. Based on these results, 61% (r = 0.7792) of the variation in Aq cortisol levels is explained by the variations in plasma cortisol levels.

Conclusion and Clinical Relevance

This study identified significant levels of cortisol in the Aq of the canine eye and positively correlated them with plasma cortisol levels. The dog may offer a representative model for further studies to help clarify the overall role of cortisol in the anterior chamber.