Liver IGF-1 and Muscle IGF-1

Discussion in 'Anything and Everything about dietary supplements' started by George, Jul 3, 2002.

  1. George

    George New Member

    I just read Bryan's article and report on the research done as to the effect of concentric exercise and eccentric exercise on IGF-1.

    The interesting thing to me - (that I didn't know) - is that only the IGF-1 from the muscle cell is useful to hypertrophy and not that from the liver.

    Is there a blood test that can tell one's level of either.

    I get my IGF-1 level checked regularly. Am I waisting my time since I don't know which it represents?

    Any thoughts or knowledge about this?

    (Oh yea! A happy and safe 4th to everyone on the HST forum)
  2. Bryan Haycock

    Bryan Haycock Administrator

    Hi George,
    I'm glad you found the article interesting.

    Muscle IGF-1 doesn't actually contribute significantly to blood levels of IGF-1.

    Muscle-specific IGF-1 is released from muscle cells that are subject to microtrauma. It then acts on the same cells that released it and on adjacent cells. It also acts on satellite cells resting in the interstitial spaces. This action on satellite cells is critical for hypertrophy.
  3. George

    George New Member


    First, thanks for the response.

    Second, is it correct to assume then that my blood level IGF-1 should be of no real concern to me regarding muscle growth.

    Several years ago my MD found my IGF-1 levels to be very low and started me on low dosage growth hormone. My IGF-1 levels are now in the upper normal level for my age (52).

    With only regard to hypertrophy - should I not be concerned about my IGF-1 blood levels?

    Thanks a lot for your input.

  4. I think you've pretty much got it. George.

    Your blood-borne IGF-1 levels will not have much of a direct influence, hypertrophy-wise, on your muscles.

    Muscle-produced IGF-1 stays in the muscle, and can't be measured by a blood test. These local levels are higher than what might likely be delivered by blood supply even with elevated levels in the blood.

    HOWEVER, stick with your doctor's recommendation as far as maintaining your health and your blood IGF-1 levels. Your blood IGF-1 levels DO play a role in many other bodily systems. If your general health is in a lower state because of IGF-1 or other hormone levels, your muscle growth will likely be inhibited as well. . . so there is an indirect connection.

    Great overall health is one of the more important factors for gaining muscle at a good clip.


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