Althesin interaction with human plasma steroid binding globulins.

Area of Science:

• Pharmacology
• Endocrinology
• Anesthesiology

Background:

• Steroid anesthetics like alphaxalone and alphadolone acetate are used in clinical practice.
• These anesthetics are known to interact with various proteins in the bloodstream.
• Testosterone-oestradiol-binding globulin (TeBG) and corticosteroid-binding globulin (CBG) are key transport proteins for steroid hormones.

Purpose of the Study:

• To measure the binding affinities of alphaxalone and alphadolone acetate for TeBG and CBG.
• To investigate the effect of Althesin (a mixture of alphaxalone and alphadolone acetate) on the transport of testosterone and cortisol in male patients.

Main Methods:

• Binding affinities were measured using human serum.
• Althesin was administered intravenously to 8 male patients.
• Concentrations of unbound and total testosterone and cortisol were monitored, along with TeBG and CBG binding parameters.

Main Results:

• Alphaxalone and alphadolone acetate exhibited high binding affinity for both TeBG and CBG.
• Althesin infusion led to a significant increase in the percentage of unbound testosterone, without altering total testosterone or TeBG binding parameters.
• Cortisol concentration increased during Althesin infusion, but unbound cortisol and CBG binding parameters remained unchanged.

Conclusions:

• Alphaxalone and/or alphadolone acetate interact with TeBG binding sites, displacing testosterone and transiently increasing unbound testosterone levels.
• The administered dose of these steroid anesthetics did not significantly alter cortisol transport during brief anesthesia in men.
• These findings highlight the potential for steroid anesthetics to influence the dynamics of steroid hormone transport proteins.