Epi-Testosterone

A -3-Ketosteroids, e.g. testosterone and epi-testosterone in urine I80°C, 20 min Pale blue induced fluorescence (Xfl = 440 nm) for A -3-ketosteroids, detection limit 5 ng. 

In the case of analytes with identical elemental formulas ( true isobars ) as positional or geometrical isomers (e.g. 11-hydroxycortisol and 21-hydroxycortisol or testosterone and epi-testosterone)—a discrimination of analyte and interfering compound is not possible with any mass analyzer—even if enabling highest mass resolution. Potentially, the disintegration pattern of isomers may be different, allowing analytical discrimination but in most cases chromatographic baseline separation of analyte and isomer prior to their MS/MS detection is required for unequivocal quantitative measurement. 

Measurement of Testosterone and Epi-testosterone in Human and Monkey Urine by Gas-Liquid Chromatography Anal. Biochem. 27(2) 343-358 (1969) ... 

Today, there are rapid, fairly accurate, and sensitive analytical techniques available to detect and measure these substances in urine or blood of the athletes suspected of illegal use. How about testosterone itself You have testosterone naturally in your body, and the testosterone injected is chemically the same compound. Can an athlete cheat and get away with it then Scientists discovered that testosterone can change itself into epi-testosterone (the positions of the OH group and the H atom (which is omitted in the figure) on C-17 on testosterone are interchanged). 

Therefore, under a natural condition there is about an equal amount of testosterone and epi-testosterone in the body fluid, blood, and urine. However, the extraneously added testosterone cannot be converted very quickly to its epimer. Hence if a urine test is conducted after (not too long after) one is doped with testosterone, the test will show an unusually high level of testosterone-to-epimer ratio. 

Doping in athletics Testosterone is a potent performance-enhancing drug that is used in both human and equestrian sports. The current method to detect testosterone abuse is based on measurement of the testosterone to epi-testosterone ratio using GC or LC/MS techniques. However, this method is not reliable because some clean individuals may naturally register a positive result and the measurement must... 

The prefix alio- is a term used to describe tlie stereoisomerism of the hydrogen atom at C-5. When the configuration differs at any other carbon atom, the prefix epi- is used (e.g., androsterone possesses a 3a-hydroxyl group, and epiandrosterone a 3P-hydroxyl group testosterone possesses a 17P-hydroxyl group, and epitestosterone a 17a-hydroxyl group).. 

Populu, J., and Jayle, M. F. Determination of Testosterone and Epi-tesyosterone in Human Urine Bull. Soc. Chim. Biol. 50(10) 1723-1737 (1968) CA 71 386w... 

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