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  1. #1
    JohnnyB's Avatar
    JohnnyB is offline AR-Hall of Famer / Retired
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    IGF-1 and heart enlargement

    When you read this you'll see that LR3 IGF-1 doesn't cuase heart enlargment

    Extracellular signal-regulated kinase and phosphoinositol-3 kinase mediate IGF-1 induced proliferation of fetal sheep cardiomyocytes.

    Sundgren NC, Giraud GD, Schultz JM, Lasarev MR, Stork PJ, Thornburg KL.


    Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon 97239, USA.

    Growth of the fetal heart involves cardiomyocyte enlargement, division, and maturation. Insulin -like growth factor-1 (IGF-1) is implicated in many aspects of growth and is likely to be important in developmental heart growth. IGF-1 stimulates the IGF-1 receptor (IGF1R) and downstream signaling pathways, including extracellular signal-regulated kinase (ERK) and phosphoinositol-3 kinase (PI3K). We hypothesized that IGF-1 stimulates cardiomyocyte proliferation and enlargement through stimulation of the ERK cascade and stimulates cardiomyocyte differentiation through the PI3K cascade. In vivo administration of Long R3 IGF-1 (LR3 IGF-1) did not stimulate cardiomyocyte hypertrophy but led to a decreased percentage of cells that were binucleated in vivo. In culture, LR3 IGF-1 increased myocyte bromodeoxyuridine (BrdU) uptake by three- to five-fold. The blockade of either ERK or PI3K signaling (by UO-126 or LY-294002, respectively) completely abolished BrdU uptake stimulated by LR3 IGF-1. LR3 IGF-1 did not increase footprint area, but as expected, phenylephrine stimulated an increase in binucleated cardiomyocyte size. We conclude that 1) IGF-1 through IGF1R stimulates cardiomyocyte division in vivo; hyperplastic growth is the most likely explanation of IGF-1 stimulated heart growth in vivo; 2) IGF-1 through IGF1R does not stimulate binucleation in vitro or in vivo; 3) IGF-1 through IGF1R does not stimulate hypertrophy either in vivo or in vitro; and 4) IGF-1 through IGF1R requires both ERK and PI3K signaling for proliferation of near-term fetal sheep cardiomyocytes in vitro.

    JohnnyB

  2. #2
    joevette's Avatar
    joevette is offline Banned
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    Very good to know, thanks.

  3. #3
    Blown_SC is offline Retired Vet
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    Hey JohhnyB... good read....

    P.S.(sorry to 'jack) What is your opinion with Clen causing heart enlargement? I'm aware of the growth of some tissue, but would you happen to have similar info regarding it?

  4. #4
    bigjohnr's Avatar
    bigjohnr is offline Associate Member
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    is IGF something you have to search for or is it over the counter? Are the results good, I am doing test eth, eq, sust 250 & HGH, I really want the fat loss.
    Thanks for your help guys

  5. #5
    biggerthanyou23 is offline New Member
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    could someone please translate that into simple English - does longr3 igf-1 causeheart enlargement or not?

  6. #6
    Blown_SC is offline Retired Vet
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    Quote Originally Posted by biggerthanyou23
    could someone please translate that into simple English - does longr3 igf-1 causeheart enlargement or not?
    The first line of the post reads:
    "When you read this you'll see that LR3 IGF-1 doesn't cause heart enlargement"

    What is confusing about this statement?

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