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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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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. |
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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. |
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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 |
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C13 to C12 Ratio of Natural and Synthetic Testosterone
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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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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. |
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C13 to C12 Ratio of Natural and Synthetic Testosterone
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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'."" |
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