Interference of an anesthetic preparation with plasma triglyceride determinations

Area of Science:

• Biochemistry
• Pharmacology
• Analytical Chemistry

Background:

• Pentobarbital sodium (Nembutal) is a common anesthetic in animal research.
• Elevated plasma triglycerides are often observed post-anesthesia.
• The cause of this elevation requires investigation.

Purpose of the Study:

• To investigate the cause of elevated plasma triglycerides after pentobarbital sodium anesthesia.
• To determine if the anesthetic solvent interferes with triglyceride measurements.
• To elucidate the mechanism of interference.

Main Methods:

• Experimental animals were anesthetized with pentobarbital sodium.
• Plasma triglyceride levels were measured using standard chemical assays.
• The role of propylene glycol, a solvent component, was analyzed.
• Oxidation of propylene glycol and its interaction with formaldehyde was studied.

Main Results:

• A significant, but false, increase in plasma triglycerides was observed.
• Propylene glycol in the solvent interferes with triglyceride determination methods.
• Propylene glycol oxidizes to formaldehyde, enhancing colorimetric reactions.
• This formaldehyde interacts with glycerol moiety of triglycerides, causing overestimation.

Conclusions:

• The observed hypertriglyceridemia is an artifact caused by propylene glycol.
• Standard triglyceride assays are susceptible to interference from anesthetic solvents.
• Care must be taken when interpreting triglyceride levels in animals anesthetized with pentobarbital sodium due to solvent effects.