Diferenciación de esteroides endógenos y exógenos mediante Cromatografía de Gases-Combustión-Espectrometría de Masas de Relaciones Isotópicas

Abstract

Urinary steroids profiles are used to control the misuse of
endogenous steroids such as testosterone and dihydrotestosterone. The
testosterone/epistestosterone ratio, measured by Gas Chromatography-Mass
Spectrometry, is used to control testosterone administration. When T/E ratio
is higher than 4, consumption of testosterone or its precursors is suspected.
Recent researches have demonstrated the effectiveness of Carbon Isotope
Ratio Mass Spectrometry to detect and confirm endogenous steroids
administration. The ratio of the two stable carbon isotopes 13C and 12C allows
the differentiation of natural and synthetic steroids because synthetic
steroids have lower 13C abundance. In fact, the carbon isotope ratios can be
used to determine endogenous steroids administration even when
testosterone/epistestosterone ratio is at its normal value. In the current work,
some of the most important aspects related to differentiation of endogenous
and exogenous steroids by means of Gas Chromatography-Combustion-
Isotope Ratio Mass Spectrometry are discussed. Also, this article provides a
rewiew about the purification and sample preparation previous to the
analysis, and diet effects on carbon isotope ratio of endogenous anabolics
steroids is presented too.