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C13 to C12 Ratio of Natural and Synthetic Testosterone



 
 
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  #1  
Old August 2nd 06, 02:25 PM posted to rec.bicycles.racing
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Posts: 3
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Maybe this belongs in rec.bicycles.racing.chemistry.organic.synthesis.

From what I've been reading, the isotope ratio of synthetic

testosterone is only somewhat different than that of natural
testosterone. Does anyone know how much the difference is? And better
yet, why is there a difference? I am assuming that all carbon in the
biosphere has the same C12/C13 ratio, and that the difference in masses
is unlikely to produce any kinetic differences during the biosynthetic
reactions, in stark contrast to H1/H2 isotopes.

Is it that a starting material is taken from the soy source and then
modified with petroleum derived reagents (which have no C13 since they
have been in the ground for millenia)?

John
Aspen Research, - www.aspenresearch.com
"Turning Questions into Answers"

Opinions expressed herein are my own and may not represent those of my
employer.

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  #3  
Old August 2nd 06, 03:52 PM posted to rec.bicycles.racing
Jonathan v.d. Sluis
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Posts: 98
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

"Dumbass" wrote in news:1154526076.715933.152870@
75g2000cwc.googlegroups.com:

I think they must be using C14. C14 is created in the atmosphere by
cosmic rays. When it get sequestered in petroleum buried and safe from
cosmic rays, it decays. So testosterone of biological origin has
higher C14 than petroleum-derived.


As I understand they use the stable isotopes 13C and 12C, referenced to a
standard 13C/12C value as measured from some kind of belemnite apparently.
The fractionation occurs because of different chemical reactions or
reaction speeds in plants and animals to make the testosterone; 12C reacts
slightly more easily and a fast reaction will result in testosterone
relatively enriched with 12C.
  #5  
Old August 2nd 06, 04:29 PM posted to rec.bicycles.racing
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Posts: 75
Default C13 to C12 Ratio of Natural and Synthetic Testosterone


wrote:
wrote:
Maybe this belongs in rec.bicycles.racing.chemistry.organic.synthesis.

From what I've been reading, the isotope ratio of synthetic

testosterone is only somewhat different than that of natural
testosterone. Does anyone know how much the difference is? And better
yet, why is there a difference? I am assuming that all carbon in the
biosphere has the same C12/C13 ratio, and that the difference in masses
is unlikely to produce any kinetic differences during the biosynthetic
reactions, in stark contrast to H1/H2 isotopes.

Is it that a starting material is taken from the soy source and then
modified with petroleum derived reagents (which have no C13 since they
have been in the ground for millenia)?


The difference is small (~3 parts per thousand PDB), but readily
measurable if you've got good technique. It arise from the fact that
synthetic testosterone is produced from plant sterols, which are lower
in 13C than animal hormones/tissues/etc. due to isotopic
discrimination.

Andy Coggan


This isotope test are very difficult. The manufacturer of the testing
equiptment says "quite regularly there are errors."

http://online.wsj.com/public/article... main_tff_top

Someone should question the UCI use of the equiptment for IRMS. The
article concludes: "The apparent sensitivity of the testosterone test's
numbers to alcohol consumption, and the announcement of partial test
results without full disclosure by the cycling union, has created a
milieu for cyclists that is "almost Kafka-esque," Dr. Davis said. "The
phrase often bandied about is 'chemical McCarthyism'.""

  #6  
Old August 2nd 06, 06:33 PM posted to rec.bicycles.racing
Geraard Spergen
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Posts: 56
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Jonathan v.d. Sluis wrote:
"Dumbass" wrote in news:1154526076.715933.152870@
75g2000cwc.googlegroups.com:


I think they must be using C14. C14 is created in the atmosphere by
cosmic rays. When it get sequestered in petroleum buried and safe from
cosmic rays, it decays. So testosterone of biological origin has
higher C14 than petroleum-derived.



As I understand they use the stable isotopes 13C and 12C, referenced to a
standard 13C/12C value as measured from some kind of belemnite apparently.
The fractionation occurs because of different chemical reactions or
reaction speeds in plants and animals to make the testosterone; 12C reacts
slightly more easily and a fast reaction will result in testosterone
relatively enriched with 12C.


C12 is 99% of all carbon, C13 is 1%, and C14 is about 1 part per 10^12.

Plants naturally have more C13 than animals so any substance (including
testosterone) produced from plants will have a higher C13 proportion
than the same substance produced by animals. Hard to believe there's
any difference in chemical reactions, it's probably due to photosynthesis.

  #7  
Old August 2nd 06, 06:42 PM posted to rec.bicycles.racing
[email protected]
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Posts: 119
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Geraard Spergen wrote:

C12 is 99% of all carbon, C13 is 1%, and C14 is about 1 part per 10^12.

Plants naturally have more C13 than animals so any substance (including
testosterone) produced from plants will have a higher C13 proportion
than the same substance produced by animals.


Nice explanation.

Hard to believe there's
any difference in chemical reactions, it's probably due to photosynthesis.


Um, isn't photosynthesis a chemical reaction? ;-)

Andy Coggan

  #10  
Old August 2nd 06, 08:03 PM posted to rec.bicycles.racing
Dumbass
external usenet poster
 
Posts: 243
Default C13 to C12 Ratio of Natural and Synthetic Testosterone


wrote:
wrote:
wrote:
Maybe this belongs in rec.bicycles.racing.chemistry.organic.synthesis.

From what I've been reading, the isotope ratio of synthetic
testosterone is only somewhat different than that of natural
testosterone. Does anyone know how much the difference is? And better
yet, why is there a difference? I am assuming that all carbon in the
biosphere has the same C12/C13 ratio, and that the difference in masses
is unlikely to produce any kinetic differences during the biosynthetic
reactions, in stark contrast to H1/H2 isotopes.

Is it that a starting material is taken from the soy source and then
modified with petroleum derived reagents (which have no C13 since they
have been in the ground for millenia)?


The difference is small (~3 parts per thousand PDB), but readily
measurable if you've got good technique. It arise from the fact that
synthetic testosterone is produced from plant sterols, which are lower
in 13C than animal hormones/tissues/etc. due to isotopic
discrimination.

Andy Coggan


This isotope test are very difficult. The manufacturer of the testing
equiptment says "quite regularly there are errors."

http://online.wsj.com/public/article... main_tff_top

Someone should question the UCI use of the equiptment for IRMS. The
article concludes: "The apparent sensitivity of the testosterone test's
numbers to alcohol consumption, and the announcement of partial test
results without full disclosure by the cycling union, has created a
milieu for cyclists that is "almost Kafka-esque," Dr. Davis said. "The
phrase often bandied about is 'chemical McCarthyism'.""


True, it is 'chemical McCarthyism'. But, in this case there is a
commie under
every just about every bed. There is a lot of doping below the
detection limits, IMO.

Justified paranoia.

 




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