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C13 to C12 Ratio of Natural and Synthetic Testosterone



 
 
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  #21  
Old August 3rd 06, 07:55 AM posted to rec.bicycles.racing
Kyle Legate
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Posts: 648
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Michael Press wrote:
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.


Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.

For what it's worth, I have done mass spec measurements on isotopically
labelled peptide mixtures (a much more complex sample than testosterone
isolated from urine) and can say the devices have become exquisitely
sensitive in the last 5 years, and they continue to double in
sensitivity roughly every year. One can only hope that the lab is using
recent state of the art to measure these samples.
Ads
  #22  
Old August 3rd 06, 09:07 AM 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 ,
Kyle Legate wrote:

Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.


Fine. Activation energy is increased by isotopic mass,
reducing the reaction rate. And you state categorically,
without anticipating any evidence to the contrary, that
mobility has nothing to do with it.

--
Michael Press
  #24  
Old August 3rd 06, 03:58 PM posted to rec.bicycles.racing
RicodJour
external usenet poster
 
Posts: 3,142
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Kyle Legate wrote:
Michael Press wrote:
Geraard Spergen wrote:
Michael Press wrote:
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.


Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.

For what it's worth, I have done mass spec measurements on isotopically
labelled peptide mixtures (a much more complex sample than testosterone
isolated from urine) and can say the devices have become exquisitely
sensitive in the last 5 years, and they continue to double in
sensitivity roughly every year. One can only hope that the lab is using
recent state of the art to measure these samples.


This is so great! I love tuning in to a TV show, say about bass
fishing, and halfway through the program there's an in depth discussion
about amine blush in fiberglass boat layup!

R

  #25  
Old August 3rd 06, 04:15 PM posted to rec.bicycles.racing
Booker C. Bense
external usenet poster
 
Posts: 1
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

-----BEGIN PGP SIGNED MESSAGE-----

In article .com,
gds wrote:


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.


- - That validates the test, but not the lab. No matter how good
the science, the process needs to be validated. It's one thing to
perform a test on a few samples with a potential publication pumping up
your CV. It's a whole 'nother thing to do it on an industrial
basis day after day.

_ The lab in this case may be just fine, but real crime labs have
to do this kind of validation, why not the WADA labs? An open
process would have the results of this kind of testing publically
available. It would be a fairly simple matter to include a few quality
control samples in every batch.

_ It's important to remember that once a bureacracy is formed
it's primarly purpose is the continuation of the bureacracy.
Regardless of what it's supposed to do, getting next year's
funding is always job #1. WADA has a huge incentive to find
cheats and zero incentive have a fair process. Unless getting
next year's funding is dependent on passing such quality
controls, their results will always be suspect.

_ Booker C. Bense

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  #26  
Old August 3rd 06, 06:22 PM posted to rec.bicycles.racing
William Asher
external usenet poster
 
Posts: 1,930
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Kyle Legate wrote:

Michael Press wrote:
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.


Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.


And they have a higher activation energy because they vibrate differently
for a given thermal energy level, in general the motion is slower and the
vibrational excursions smaller. That is a "mobility" issue in the sense
that the intermolecular atomic motion is less because the mass is greater
and the overall energy at a given temperature is constant. So you have to
give the system more energy to get the molecules vibrating enough to reach
the activation threshold. Or maybe a better way to say it is that for a
given Boltzman energy distribution, more lighter molecules will have enough
energy to be above the activation threshold than heavier molecules.

The fractionation across a gas-liquid interface is a translational mobility
issue in general unless there is some sort of reaction going on along with
the phase transition. In that case the diffusivity is roughly proportional
to the mean molecular speed, which is a function of the molecular mass.
Increase the mass, decrease the speed, decrease the diffusivity, decrease
the flux across the gas-liquid boundary.

Quantum tunneling (QT) can overcome some of the kinetic isotopic
fractionation for hydrogen/deuterium but QT is also mass-dependent so there
is also isotopic separation in this process as well. QT of heavier atoms
has only been observed in a few weird systems that I know of but also would
be subject to isotopic fractionation, though not to as large a degree as
kinetic fractionation.

--
Bill Asher
  #27  
Old August 3rd 06, 07:48 PM posted to rec.bicycles.racing
Kyle Legate
external usenet poster
 
Posts: 648
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

William Asher wrote:
Kyle Legate wrote:

Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.



And they have a higher activation energy because they vibrate differently
for a given thermal energy level, in general the motion is slower and the
vibrational excursions smaller. That is a "mobility" issue in the sense
that the intermolecular atomic motion is less because the mass is greater
and the overall energy at a given temperature is constant.


Aha. When I saw mobility I thought you were referring to the rate of
substrate delivery to enzyme active sites. Thinking like a biochemist,
and not as a chemist.
  #28  
Old August 3rd 06, 08:29 PM posted to rec.bicycles.racing
William Asher
external usenet poster
 
Posts: 1,930
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

Kyle Legate wrote:

William Asher wrote:
Kyle Legate wrote:

Mobility has nothing to do with it. Heavier isotopes have a higher
activation energy, so they react slower. A phenomenon called hydrogen
tunneling can overcome this but it is extremely rare.



And they have a higher activation energy because they vibrate
differently for a given thermal energy level, in general the motion
is slower and the vibrational excursions smaller. That is a
"mobility" issue in the sense that the intermolecular atomic motion
is less because the mass is greater and the overall energy at a given
temperature is constant.


Aha. When I saw mobility I thought you were referring to the rate of
substrate delivery to enzyme active sites. Thinking like a biochemist,
and not as a chemist.


I didn't define it quite correctly at first, I think. It's also confusing
because there are two fractionation processes going on in plants, the first
as CO2 goes across the stoma into the leaf, the second as the CO2 gets used
to make sugar and cellulose and whatever. The first process is a true
mobility effect, the second is the activation effect.

--
Bill Asher
  #29  
Old August 3rd 06, 10:54 PM posted to rec.bicycles.racing
Tom Kunich
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Posts: 6,456
Default C13 to C12 Ratio of Natural and Synthetic Testosterone

"k.papai" wrote in message
oups.com...
wrote:
wrote:

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.


There's more to this than meets the eye - the amount of testosterone in
urine is VERY small. The amount used to TEST is a great deal smaller. That
means that the differential analysis can have large errors simply from
chance.

Think of it this way - if you have three molecules of C12 and one of C13
NORMALLY all it takes if for an addition C13 to be in a test sample to
demonstrate a change of from 4/1 to 4/2 - 25% vs 50%. A 100% increase.

Here's another source of error - the idea is to filter out everything BUT
testosterone using a column of some sort and then to break the testosterone
down into its components molecules and then use a mass spectrometer to
measure the weight.

Columns are far from perfect and since the absolute quantities are low, it
is fairly easy for the technician to catch more than the testosterone in the
mix and to break down other components of the urine as well. Yet another
source of error.

What's more - unless the observer is a specifically and highly trained
individual in the art of GC/Mass Spec, it would be highly unlikely that he
could even detect a faulty separation process. And believe me, it IS and art
and not a science.


  #30  
Old August 3rd 06, 10:57 PM posted to rec.bicycles.racing
Tom Kunich
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Posts: 6,456
Default C13 to C12 Ratio -- Is Floyd a Vegetarian?

wrote in message
ups.com...

It would. However, this is why the "reference material" used is another
endogenous steroid, not some testosterone taken off the shelf. (Those
who perform studies using stable isotopically labeled tracers are
exceedingly familiar with the need to obtain a baseline or background
sample prior to tracer administration to account for the natural
abundance of, e.g., 13C in whatever is being traced. The principle is
the same here.)


As I was saying Andy, using another steroid might not be a good idea. And
the sample may have been poluted with other carbon sources that are more
immediate than steroid production which is a great deal more detailed. So it
is possible that there can be radically different ratios of C12/C13 in one
component of urine and another component.


 




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