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  1. #1
    peachfuzz's Avatar
    peachfuzz is offline Anabolic Member
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    Tamoxifen Blocks HCG Induced Leydig Cell Desensitization

    This was taken from another board and thought it was woth sharing...

    Tamoxifen Blocks HCG Induced Leydig Cell Desensitization
    HCG induced testicular desensitization seems to be a hot topic. There are a number of studies showing that concomitant use of Nolvadex ameliorates this. The first abstract suggests that HCG at least partially blocks the conversion of 17 alpha-hydroxyprogesterone (17 OHP), a testosterone precursor, to testosterone. This effect is suppressed by Nolvadex.

    The second abstract seems to indicate that estrogen may not be the only culprit, since Nolvadex plus HCG does not increase T levels any more than HCG alone, even though the combination reduces desensitization.

    Since we are trying to avoid this desensitization so when we quit the HCG our testes respond to our endogenous LH, it makes sense to always use nolvadex with HCG to at least help the problem, if not solve it completely.


    J Clin Endocrinol Metab 1980 Nov;51(5):1026-9

    Tamoxifen suppresses gonadotropin-induced 17 alpha-hydroxyprogesterone accumulation in normal men.

    Smals AG, Pieters GF, Drayer JI, Boers GH, Benraad TJ, Kloppenborg PW.

    Intramuscular administration of 1500 IU hCG daily for 3 days induced a transient accumulation of 17 alpha-hydroxyprogesterone (17 OHP) relative to testosterone (T) in normal men, reaching its maximum 24 h after the first injection (17 OHP to T ratio, 1.7 +/- 0.3 times baseline; P < 0.01). Simultaneous administration of hCG and the estrogen antagonist tamoxifen (20 mg twice daily) almost completely abolished the hCG-induced steroidogenic block localized between 17 OHP and T (17 OHP to T ratio at 24 h, 1.1 +/- 0.1 times baseline; P < 0.01 vs. hCG alone). These data indirectly suggest that, in man, the hCG-induced steroidogenic lesion might be mediated through its estrogen-stimulating effect.



    Andrologia 1991 Mar-Apr;23(2):109-14

    Effect of an antiestrogen on the testicular response to acute and chronic administration of hCG in normal and hypogonadotropic hypogonadic men: tamoxifen and testicular response to hCG.

    Levalle OA, Suescun MO, Fiszlejder L, Aszpis S, Charreau E, Guitelman A, Calandra R.

    Division Endocrinologia, Hospital Carlos Durand, Instituto de Biologia y Medicina Experimental, Buenos Aires, Argentina.

    The effect of the antiestrogen tamoxifen (Tx) on the acute and chronic hCG administration was evaluated in patients with hypogonadotropic hypogonadism (HH) and in normal men. An hCG test (5000 IU hCG) was performed before, after two months of hCG administration (2000 IU hCG three times weekly) and after two months of hCG + Tx (2000 IU hCG three times weekly plus 20 mg/day of tamoxifen). Blood samples were obtained before and following 24 and 72 h of every test to determine T, E, 17OHP and SHBG. T increased only in HH with both treatments (X +/- SEM: Basal: 97.9 +/- 19.7; hCG: 237.7 +/- 43.2; hCG +/- Tx: 204.7 +/- 10.7 ng/100 ml). 17OHP rose with hCG alone, but not with hCG + Tx in both groups. E, SHBG and 17OHP/T ratio did not change after treatments. hCG tests: E increased 24 h following hCG administration in every test. The ratio 17OHP/T rose at 24 h in the first and second test but in the third test it did not change. These results support the role of E in the acute hCG-induced Leydig cell desensitization. However, the association of Tx does not improve T serum levels, suggesting that E might not be the unique factor involved in the mechanisms for testicular desensitization.

  2. #2
    WARMachine's Avatar
    WARMachine is offline Post Cycle Extraordinaire~GOT PCT?
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    Already knew this...
    Nolvadex (Tamoxifen Citrate) : Nolvadex is a SERM. It selectively binds to certain estrogen receptors, effectively blocking the estrogen and stopping unwanted sides such as gyno. It DOES NOT lower estro levels in the blood, it only blocks it from binding to certain receptors. It also helps your blood fat levels. It does not suppress LH, blocks desired estro receptors and helps stop HCG from desensitizing your testicles to natural LH. Nolva should be used during HCG therapy, at 20 mg a day, for the reason i just mentioned. Can be used during cycle if you see signs of gyno. Its mainly used to block the estrogen spike when you come off cycle, and should be used right through to the end until natural test levels are back. One drawback to consider about Nolva is that it may cause progesterone receptors to become more sensitive. This means that while using progestins such as Deca or Tren, you may become more sensetive to progestin related gyno.

    But awesome find brother!

  3. #3
    LATS60's Avatar
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    Iv'e read this before, apart from having little bearing for the steroid user (because we dont use enough hCG to cause desensitization) the guy has totally misinterpreted the article he quoted.
    Also it's seems this guy has fallen into the myth trap, exogenous hCG can work along side you're natural LH production, so to say this.
    "Since we are trying to avoid this desensitization so when we quit the HCG our testes respond to our endogenous LH, it makes sense to always use nolvadex with HCG to at least help the problem, if not solve it completely".
    Is wrong.
    Of course it can be wise be take nolva with hCG because of the 300% rise in testosterone and the subsequent aromatisation to estrogen, especially if you are gyno prone.

  4. #4
    peachfuzz's Avatar
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    Lats, what if someone were to use high enough doses to desensitize Leydig cells? then aside from the assumption exogenous HCG can work alongside natural LH levels would this article hold some validity? I have seen alot of people on this board running HCG in much higher doses then are neccesary.

    Also according to the article unless im reading it wrong it shows no differenct in T levels with with the concurrent administration of Tamoxifen .

    Quote Originally Posted by LATS60 View Post
    Of course it can be wise be take nolva with hCG because of the 300% rise in testosterone and the subsequent aromatisation to estrogen, especially if you are gyno prone.
    However, the association of Tx does not improve T serum levels, suggesting that E might not be the unique factor involved in the mechanisms for testicular desensitization.

  5. #5
    LATS60's Avatar
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    Quote Originally Posted by peachfuzz View Post
    Lats, what if someone were to use high enough doses to desensitize Leydig cells? then aside from the assumption exogenous HCG can work alongside natural LH levels would this article hold some validity? I have seen alot of people on this board running HCG in much higher doses then are neccesary.

    Also according to the article unless im reading it wrong it shows no differenct in T levels with with the concurrent administration of Tamoxifen.
    Well it's not an assumption first off mate (thought you new me better LOL) it's a medical fact, taken from the many hCG and hypogonadic trials.
    10000iu has been used in trials in one shot, this caused desensitization/leydig cell receptor saturation for 96 hrs.
    Maybe i didn't make myself clear, i mean't that hCG alone gives a 300% rise in test and subsequent aromatisation to estrogen, so gyno prone individuals might want to run nolva with hCG anyway.

    I don't give any credit to what the guy has assumed TBH, as i said he has misinterpreted the abstract, therefore his idea is flawed from the start, but the abstract in itself makes valid points.
    IMO and from the research i have done adex would be a better choice especially if you start it a week before Hcg therapy, there are a few studies done on androgen priming with AI's before hCG use, results look promising.

  6. #6
    peachfuzz's Avatar
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    Quote Originally Posted by LATS60 View Post
    Well it's not an assumption first off mate (thought you new me better LOL) it's a medical fact, taken from the many hCG and hypogonadic trials.
    10000iu has been used in trials in one shot, this caused desensitization/leydig cell receptor saturation for 96 hrs.
    Maybe i didn't make myself clear, i mean't that hCG alone gives a 300% rise in test and subsequent aromatisation to estrogen, so gyno prone individuals might want to run nolva with hCG anyway.

    I don't give any credit to what the guy has assumed TBH, as i said he has misinterpreted the abstract, therefore his idea is flawed from the start, but the abstract in itself makes valid points.
    IMO and from the research i have done adex would be a better choice especially if you start it a week before Hcg therapy, there are a few studies done on androgen priming with AI's before hCG use, results look promising.
    Ah now I get it. Thanks for clearing that up.

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