Effects of anesthesia with isoflurane on plasma concentrations of adrenocorticotropic hormone in samples obtained from the cavernous sinus and jugular vein of horses.

The research studied the impact of anesthesia on the levels and pulsatility of the hormone ACTH in the blood of horses. The study found that anesthesia significantly reduces ACTH concentration in blood samples collected from a particular area of the brain called the cavernous sinus.

Objective and Methodology

• The study was aimed at determining the effects of anesthesia on the plasma concentrations and pulsatility of adrenocorticotropic hormone (ACTH), a hormone that plays a key role in the functions of the adrenal glands, particularly during times of stress.
• The test subjects were six clinically normal adult horses. Catheters were placed in a jugular vein and into the cavernous sinus, an area within the brain, of these horses via a superficial facial vein.
• The blood sampling and measurement process spanned across two days. On the first day, blood samples were collected from the cavernous sinus every five minutes for one hour. On the second day, horses were sedated and anesthetized, post which the same blood sample protocol was followed.
• Testing for ACTH levels was done with help of a commercially available sandwich assay. Sophisticated statistical techniques, including generalized estimating equations and an automated deconvolution algorithm, were used to measure the effects of anesthesia on ACTH levels and pulsatility.

Results and Conclusion

• The results from the testing showed that anesthesia significantly reduces the concentration of ACTH in blood samples collected from the cavernous sinus.
• This suggests that the anesthesia method used in the study alters ACTH levels and this consideration should be taken into account when interpreting ACTH concentrations for clinical diagnosis and treatment.
• One interpretation might be that ACTH concentrations in cavernous sinus blood may not be reliable indicators for the success of partial ablation of the pituitary gland. Anesthesia, according to the results of this study, could potentially skew such interpretations.