Studies related to the metabolism of anabolic steroids in the horse: 19-nortestosterone.

The research examines the metabolism of the anabolic steroid 19-nortestosterone in horses. This process was studied using 14C-labelled material and identified two metabolites through spectroscopy methods.

Overview of the Study

• The study focuses on understanding how the anabolic steroid called ’19-nortestosterone’ is metabolized in the body of a horse. This type of steroid is often used in sports like horse racing to enhance the performance of the animals.
• The researchers used a cross-bred horse for this study, which was subjected to 19-nortestosterone that had been labelled with Carbon-14 (14C). This radioactive carbon isotope helped to track the steroid through the metabolism process in the horse.

Identification of Metabolites

• The researchers isolated two neutral metabolites from the horse’s urinary extracts as a part of the study. This was done using a technique called column chromatography which is used to purify individual chemical compounds from mixtures.
• The isolated metabolites were identified as ‘isomers of 3-hydroxyestran-17-one’ and ‘estrane-3, 17-diol’. An isomer is a compound with the same chemical formula but different physical properties, making their identification crucial to understand the changes happening in the horse’s body due to the steroid.
• The identification of these metabolites was done through a technique known as Gas Liquid Chromatography – Mass Spectroscopy (g.l.c.-mass spectrometry). This method is used to separate, identify, and quantify compounds based on their mass-to-charge ratio.

Investigation of Stereochemistry

• The researchers also investigated the stereochemistry of the two metabolites. Stereochemistry is the study of how the properties and reactions of molecules are affected by their spatial arrangement.
• The researchers compared the retention times of the trimethylsilyl (TMS) derivatives of metabolites with standard steroids. A TMS derivative is a compound where a trimethylsilyl group is bonded to an atom in a molecule, changing its behavior in GC-MS analysis. The ‘retention time’ in this context refers to the time taken by a particular compound (in this case, the metabolites) to pass through a GC-MS system. Comparing these times with known standards can help identify the analyzed compounds.