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C13 to C12 Ratio of Natural and Synthetic Testosterone



 
 
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  #11  
Old August 2nd 06, 09:11 PM posted to rec.bicycles.racing
Michael Press
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Posts: 1,100
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

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


What is photosynthesis if not a chemical reaction? At
least make your beliefs consistent. I suggest you take up
creationism. If that is not to your liking you will have
to eat your beliefs, because we have known for many
decades that chemical reaction rates for C12, C13, and C14
are different.

--
Michael Press
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  #12  
Old August 2nd 06, 09:21 PM posted to rec.bicycles.racing
k.papai
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Posts: 37
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."


Exactly my point from yesterday.
I don't see how isotopic tests of C12/C13 could hold any value with
WADA or UCI.

The amounts being tested are phenomonally miniscule.

You need hard evidence and so far there is NONE.

-Ken


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'.""


  #13  
Old August 2nd 06, 10:09 PM posted to rec.bicycles.racing
Ron Ruff
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Posts: 1,304
Default C13 to C12 Ratio of Natural and Synthetic Testosterone


wrote:
Does anyone know how much the difference is? And better
yet, why is there a difference?


From a NYTimes article posted to ST:


"The test starts with an isolation of testosterone from the athlete's
urine. Then chemists determine the makeup of the carbon atoms that form
the backbone of testosterone.

Ordinarily, carbon atoms are made up of six protons and six neutrons,
giving them an atomic weight of 12. But occasionally, they have an
extra neutron, giving them an atomic weight of 13.

By chance, soy plants are the source of most pharmaceutical
testosterone. They tend to have slightly less carbon-13 than other
plants that are more abundant in the human diet. Humans make
testosterone from the food they eat, so their testosterone typically
has more carbon-13 than the testosterone that drug companies synthesize
from soy.

But these differences are tiny.

The test determines whether the testosterone in the athlete's urine
has less carbon-13 than another naturally occurring hormone in the
urine, like cholesterol. The test is considered positive when the
carbon isotope ratio - the amount of carbon-13 compared to carbon-12
- is three or more units higher in the athlete's testosterone than
it is in the comparison hormone. It is evidence that the testosterone
in the urine was not made by the athlete's body. Landis's
difference was 3.99, according to his own doctor."

  #14  
Old August 2nd 06, 10:33 PM posted to rec.bicycles.racing
Geraard Spergen
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Posts: 56
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Michael Press wrote:

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



What is photosynthesis if not a chemical reaction? At
least make your beliefs consistent. I suggest you take up
creationism. If that is not to your liking you will have
to eat your beliefs, because we have known for many
decades that chemical reaction rates for C12, C13, and C14
are different.


Oh man, that's harsh!

Differing chemical reaction rates cannot explain why plants have more
C13 to begin with. You have to explain why C13 is more likely to become
part of a plant than to become part of something else... or perhaps you
could propose that flora C12 is more likely to absorb an itinerant
neutron than fauna C12.

Chemistry is mostly about electrons, photons are absorbed in the
nucleus. I reasoned (perhaps incorrectly) that photosynthesis involves
photons being absorbed by neutrons and that C13 had a higher cross
section for photon absorption than did C12 and that this might account
for plants having a higher proportion of C13 than non-photosynthesizing
organisms. It may be a dumbass theory, but it can't hold a candle to
creationism.



  #15  
Old August 2nd 06, 11:14 PM posted to rec.bicycles.racing
William Asher
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Posts: 1,930
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Geraard Spergen wrote:


Differing chemical reaction rates cannot explain why plants have more
C13 to begin with. You have to explain why C13 is more likely to
become part of a plant than to become part of something else... or
perhaps you could propose that flora C12 is more likely to absorb an
itinerant neutron than fauna C12.

Chemistry is mostly about electrons, photons are absorbed in the
nucleus. I reasoned (perhaps incorrectly) that photosynthesis
involves photons being absorbed by neutrons and that C13 had a higher
cross section for photon absorption than did C12 and that this might
account for plants having a higher proportion of C13 than
non-photosynthesizing organisms. It may be a dumbass theory, but it
can't hold a candle to creationism.


Photosynthesis is about chlorophyll absorbing multiple red photons and
using that sum energy to cleave water and co2 to make sugar, sort of.
Photons in the visible region are mainly absorbed by the electrons in the
bonding orbitals of the molecules (or the outer electrons for atoms (inner
electronic transitions are generally in the x-ray/vuv region for atoms)).
Nuclear spin transitions, I vaguely recall, can be in the visible region,
but their transitions strengths are weak and nearly always visible spectra
of atoms and molecules are determined by the electronic structure. Nuclear
energy transitions are up in the gamma ray region. Anyway, I am too lazy
to look this next bit up but I think it is more or less correct, the thing
about chlorophyll that is interesting is that it absorbs photons and
transfers that energy into vibrational modes. That vibrational energy
builds up in the porphin ring and is then used to initiate breaking apart
of CO2 and H2O. Or something like that anyway.

Biologically produced carbon compounds have *less* of the heavier isotopes,
not more. Isotopic fractionation occurs because in general heavier things
don't move as fast (both in a vibrational sense and in a translational
sense) and it is the kinetic energy of motion, to a large degree, that
makes molecules react. There is sort of a double whammy for plants in that
the CO2 fractionates going through the stoma since the 13CO2 is not as
efficiently transported into the plant to begin with, this is mainly a
translational effect. Once in the plant, the heavier isotope CO2 doesn't
react as readily (which I think is the vibrational effect).

--
Bill Asher
  #16  
Old August 2nd 06, 11:34 PM posted to rec.bicycles.racing
[email protected]
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Posts: 75
Default C13 to C12 Ratio of Natural and Synthetic Testosterone


Ron Ruff wrote:
wrote:
Does anyone know how much the difference is? And better
yet, why is there a difference?


From a NYTimes article posted to ST:


"The test starts with an isolation of testosterone from the athlete's
urine. Then chemists determine the makeup of the carbon atoms that form
the backbone of testosterone.

Ordinarily, carbon atoms are made up of six protons and six neutrons,
giving them an atomic weight of 12. But occasionally, they have an
extra neutron, giving them an atomic weight of 13.

By chance, soy plants are the source of most pharmaceutical
testosterone. They tend to have slightly less carbon-13 than other
plants that are more abundant in the human diet. Humans make
testosterone from the food they eat, so their testosterone typically
has more carbon-13 than the testosterone that drug companies synthesize
from soy.

But these differences are tiny.

The test determines whether the testosterone in the athlete's urine
has less carbon-13 than another naturally occurring hormone in the
urine, like cholesterol. The test is considered positive when the
carbon isotope ratio - the amount of carbon-13 compared to carbon-12
- is three or more units higher in the athlete's testosterone than
it is in the comparison hormone. It is evidence that the testosterone
in the urine was not made by the athlete's body. Landis's
difference was 3.99, according to his own doctor."


For the purpose of discusion, I will accept everything you say. The
problem I have is that WADA/UCI have not produced a study of an
appropriate sized sample, say 100 or 1,000, which was tested blind.
In the study technicians would given samples of unknown content (to
them) and told to identify which of the samples had exogenous T and
which did not.. Of course many of the samples would have idential
composition, and be given to different individuals (from different
labs). Then the resulting data should be made known to the public so
it can be reveiwed and commented upon.

Said another way, describing a complex test does not answer the
question "does the test actually do what it is claimed to do." The
thrust of the machine manufacturer's comments is the answer is "no."

  #17  
Old August 2nd 06, 11:52 PM posted to rec.bicycles.racing
gds
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Posts: 375
Default C13 to C12 Ratio of Natural and Synthetic Testosterone


wrote:

For the purpose of discusion, I will accept everything you say. The
problem I have is that WADA/UCI have not produced a study of an
appropriate sized sample, say 100 or 1,000, which was tested blind.
In the study technicians would given samples of unknown content (to
them) and told to identify which of the samples had exogenous T and
which did not.. Of course many of the samples would have idential
composition, and be given to different individuals (from different
labs). Then the resulting data should be made known to the public so
it can be reveiwed and commented upon.

Said another way, describing a complex test does not answer the
question "does the test actually do what it is claimed to do." The
thrust of the machine manufacturer's comments is the answer is "no."


The process that you describe has parts that make some parts that
don't.
As far as getting a valid and reliable test. Of course! In fact for a
test to be considered valid and reliable a process much like what you
describe is what happens. A test is developed and the results are
published. If the publication is a peer reviewed journal then a panel
of experts reviews the study methodology and determines that there is
merit (not necessarily that is correct) to its publication. The
publication will include a detailed description of the methodology so
that others researchers in other labs can try to replicate the results.
Both positive and negative results will then be published and the
scientific community can judge the level of value of the test.

So, that pretty much is consistent with your desire for lots of folks
to perfomr the test and see how accurate (reliable/valid) it is.

But then you want the "public" to comment. On what would the public
comment? Of what value would it be? The discussion is about highly
technical and complex procedures. Of what use would my degree in
economics be in judging the worth of these studies. Yes, with a bit of
logic one can see summary results and make a dilletantish judgement but
not a really scientific judgement. I sure don't put much stock in a
chemist's opinion of my currency exchange rate prediction model. But a
lot of other economists have liked it.

  #19  
Old August 3rd 06, 03:24 AM posted to rec.bicycles.racing
RonSonic
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Posts: 2,658
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

On 2 Aug 2006 15:52:35 -0700, "gds" wrote:

But then you want the "public" to comment. On what would the public
comment? Of what value would it be? The discussion is about highly
technical and complex procedures. Of what use would my degree in
economics be in judging the worth of these studies. Yes, with a bit of
logic one can see summary results and make a dilletantish judgement but
not a really scientific judgement. I sure don't put much stock in a
chemist's opinion of my currency exchange rate prediction model. But a
lot of other economists have liked it.


There's room for cross-discipline opinion. Too often a field will be so caught
up in its own assumptions that it won't see what is obvious from another
perspective. You are economist, you've seen this happen in your field in your
life time.

Now that chemist knows his limitations (only if he's smart and honest) and could
only ask the sort of questions that a really bright guy who understands science
in general could put to you about your model. But, I'm sure you could see that
he might have a worthwhile perspective on it.

Ron
  #20  
Old August 3rd 06, 05:56 AM posted to rec.bicycles.racing
Michael Press
external usenet poster
 
Posts: 1,100
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

In article ,
Geraard Spergen wrote:

Michael Press wrote:

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



What is photosynthesis if not a chemical reaction? At
least make your beliefs consistent. I suggest you take up
creationism. If that is not to your liking you will have
to eat your beliefs, because we have known for many
decades that chemical reaction rates for C12, C13, and C14
are different.


Oh man, that's harsh!

Differing chemical reaction rates cannot explain why plants have more
C13 to begin with. You have to explain why C13 is more likely to become
part of a plant than to become part of something else... or perhaps you
could propose that flora C12 is more likely to absorb an itinerant
neutron than fauna C12.

Chemistry is mostly about electrons, photons are absorbed in the
nucleus. I reasoned (perhaps incorrectly) that photosynthesis involves
photons being absorbed by neutrons and that C13 had a higher cross
section for photon absorption than did C12 and that this might account
for plants having a higher proportion of C13 than non-photosynthesizing
organisms. It may be a dumbass theory, but it can't hold a candle to
creationism.


But look, you are `reasoning' from your beliefs. Chemical
reaction rates are also about mobility of reactants. That
C13 is heavier than C12 affects its mobility. Bill*Asher
talks about some details; to which I add that
respiration, glycolysis, and photosynthesis are largely
reversible reaction sequences in which single step
fractionations are additive leading to a much increased
discrimination factor for the overall process. This
situation is analogous with the high efficiency with which
a multiple-plate fractionating column effects the
separation of liquids differing only slightly in their
vapor pressures when a single distillation step achieves
but little separation.

--
Michael Press
 




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