Development of a method which discriminates between endogenous and exogenous beta-boldenone.

Area of Science:

• Veterinary Pharmacology
• Analytical Chemistry
• Food Safety

Background:

• Boldenone is an anabolic steroid sometimes illegally administered to cattle.
• Distinguishing between endogenous and exogenous boldenone metabolites is crucial for residue control.
• Fecal contamination can be a source of boldenone and its metabolites in urine samples.

Purpose of the Study:

• To develop and validate an analytical method to differentiate boldenone and its metabolites from fecal contamination markers.
• To investigate the origin of boldenone metabolites found in calf urine samples within a national residue control program.

Main Methods:

• Liquid chromatography-mass spectrometry (LC-MS) was used for screening approximately 10,000 urine samples.
• Developed method discriminates between unconjugated boldenone, its glucuronide and sulphate conjugates, 6beta-hydroxy-17alpha/beta-boldenone, and coprostanol.
• Analysis focused on 261 suspect samples for conjugation state, specific metabolites, and fecal markers.

Main Results:

• Alfa-boldenone, a major metabolite, and unconjugated beta-boldenone were frequently detected, often linked to fecal contamination.
• The minor metabolite 6beta-hydroxy-17alpha/beta-boldenone was not found in any tested samples.
• Absence of 6beta-hydroxy-17alpha/beta-boldenone suggests endogenous origin for alpha-boldenone conjugates.

Conclusions:

• The presence of unconjugated beta-boldenone and alpha-boldenone conjugates does not indicate illegal boldenone ester administration.
• Fecal contamination is a significant factor to consider when interpreting boldenone findings in calf urine.
• Conjugated beta-boldenone was not found to be of endogenous origin.