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  1. #1
    oswaldosalcedo's Avatar
    oswaldosalcedo is offline Senior Member
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    Differences in plasma binding of LR3 and IGF1 (human and others)

    Differences in the association of insulin-like growth factor-I (IGF-I) and IGF-I variants with rat, sheep, pig, human and chicken plasma-binding proteins.

    Lord AP, Bastian SE, Read LC, Walton PE, Ballard FJ.

    Child Health Research Institute, North Adelaide, South Australia.

    "Associations between labelled insulin -like growth factors (IGFs) and IGF-binding proteins in plasma have been compared in the rat, sheep, human, pig and chicken. The IGFs tested were recombinant human IGF-I, the truncated variant, des(1-3)IGF-I, and LR3IGF-I, an extended form that had been engineered so as to minimize interactions with IGF-binding proteins. Marked species differences were demonstrated, notably that the IGF-I variants which exhibited extremely weak binding in rat plasma bound significantly in plasma from the other species. This result was shown both by size-exclusion chromatography of labelled IGFs added to plasma, in which the extent of variant IGF-I binding decreased in the order sheep > human > pig = chicken > rat, and by competition for labelled IGF-I binding in vitro, in which the order was pig = chicken > sheep > human > rat. Notwithstanding these differences, the two IGF-I variants showed only slight between-species binding differences when tested with purified rat, sheep and human IGF-binding protein-3. Ligand blotting experiments with plasma from the five species similarly showed a consistent pattern in that IGF-I binding was much greater than des(1-3)IGF-I binding, which in turn was greater than LR3IGF-I binding"

    less binding,more powerful.
    Last edited by oswaldosalcedo; 11-07-2005 at 01:50 PM.

  2. #2
    Seattle Junk's Avatar
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    Quote Originally Posted by oswaldosalcedo
    Differences in the association of insulin-like growth factor-I (IGF-I) and IGF-I variants with rat, sheep, pig, human and chicken plasma-binding proteins.

    Lord AP, Bastian SE, Read LC, Walton PE, Ballard FJ.

    Child Health Research Institute, North Adelaide, South Australia.

    "Associations between labelled insulin -like growth factors (IGFs) and IGF-binding proteins in plasma have been compared in the rat, sheep, human, pig and chicken. The IGFs tested were recombinant human IGF-I, the truncated variant, des(1-3)IGF-I, and LR3IGF-I, an extended form that had been engineered so as to minimize interactions with IGF-binding proteins. Marked species differences were demonstrated, notably that the IGF-I variants which exhibited extremely weak binding in rat plasma bound significantly in plasma from the other species. This result was shown both by size-exclusion chromatography of labelled IGFs added to plasma, in which the extent of variant IGF-I binding decreased in the order sheep > human > pig = chicken > rat, and by competition for labelled IGF-I binding in vitro, in which the order was pig = chicken > sheep > human > rat. Notwithstanding these differences, the two IGF-I variants showed only slight between-species binding differences when tested with purified rat, sheep and human IGF-binding protein-3. Ligand blotting experiments with plasma from the five species similarly showed a consistent pattern in that IGF-I binding was much greater than des(1-3)IGF-I binding, which in turn was greater than LR3IGF-I binding"

    less binding,more powerful.

    arghhhh, what does this study prove? It would be a better study if they would show the level of muscle hypertrophy or actual LBM in each species.

  3. #3
    oswaldosalcedo's Avatar
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    Quote Originally Posted by Seattle Junk
    arghhhh, what does this study prove? It would be a better study if they would show the level of muscle hypertrophy or actual LBM in each species.
    not yet, but is the first with LR3.
    it explain why LR3 is stronger than IGF1.
    and there is studies with igf, just multiply by 1.5 and that is all.
    that`s that.

    but pinn answered that question at:
    http://forums.steroid.com/showthread.php?t=204470
    post 6


    where you were seatle?

  4. #4
    Seattle Junk's Avatar
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    Quote Originally Posted by oswaldosalcedo
    not yet, but is the first with LR3.
    it explain why LR3 is stronger than IGF1.
    and there is studies with igf, just multiply by 1.5 and that is all.
    that`s that.

    but pinn answered that question at:
    http://forums.steroid.com/showthread.php?t=204470
    post 6


    where you were seatle?
    Working a lot....been spending more time at the local office rather than my home office. Thanks for asking.....

  5. #5
    JohnnyB's Avatar
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    The 13 extra amino acids are what causes LR3 to bind poorly to IGF-1 BP

    JohnnyB

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