misconception on the half life of IGF-1 Long R3

  1. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0

    misconception on the half life of IGF-1 Long R3


    I have heard it said many times that IGF-1 longR3 has an extended half life in the body compared to regular IGF-1

    that simply is not true. IGF-1 actually has a longer half life (several hours) as it is able to quickly bind to binding proteins which protect it from proteases. long R3 cannot bind to these proteins, so it is easily broken down. i am not just saying this, it has been shown in published research

    IGF-1 binds in large part to binding protein 3, which protects the peptide and delivers it to sites in the body where it is needed. there are other binding proteins too, but these are ones which sequester the igf-1 and lead it out of the body

    longR3 however can have advantages as it is more potent. So for fast acting potency, perhaps for localized action or post workout acute effects, it probably is preferable

  2. Bananas
    Board Sponsor
    TripDog's Avatar
    Stats
    5'10"  201 lbs.
    Join Date
    Mar 2006
    Posts
    10,084
    Answers
    0


    that's the first time i ever heard that?? usually everyone says it the other way around??
    The LORD is my rock, my fortress, and my savior; my God is my rock, in whom I find protection. He is my shield, the power that saves me, and my place of safety.-Psalm 18:2
  3. Registered User
    Jayhawkk's Avatar
    Stats
    5'8"  230 lbs.
    Join Date
    Dec 2003
    Age
    39
    Posts
    12,791
    Answers
    0


    Seems in this industry just give it time and everything will swing 180 degrees. It's like the Culture Club all over again.
    •   
       

  4. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by TripDog View Post
    that's the first time i ever heard that?? usually everyone says it the other way around??
    this is because so many people neglect doing PRIMARY RESEARCH

    by primary research i mean looking at real scientific data. real studies published in professional journals

    so many do internet searches and take the beliefs of articles or blogs written by other bodybuilders as fact. They consider this to be adequate research to discover facts about something. But this makes the assumption that these bodybuilding gurus they believe are correct in their conclusions in the first place. Many times, they are not. Many times an accepted belief has its origins in someones unsubstantiated theory or guess or wishful thinking, and not in documented scientific evidence

    But by doing this you only allow a falsehoold to gain acceptance, often to the point where its considered a fundamental truth. And then people take that fundamental truth and go on to make further deductions and further theories based upon it.

    Eventually it turns into an ungodly tangled mess of misinformation and confusion. This has been a pet peeve of mine for years and years. It has been the source of me wanting to pull my hair out many a time
  5. Bananas
    Board Sponsor
    TripDog's Avatar
    Stats
    5'10"  201 lbs.
    Join Date
    Mar 2006
    Posts
    10,084
    Answers
    0


    Quote Originally Posted by Patrick Arnold View Post
    this is because so many people neglect doing PRIMARY RESEARCH

    by primary research i mean looking at real scientific data. real studies published in professional journals

    so many do internet searches and take the beliefs of articles or blogs written by other bodybuilders as fact. They consider this to be adequate research to discover facts about something. But this makes the assumption that these bodybuilding gurus they believe are correct in their conclusions in the first place. Many times, they are not. Many times an accepted belief has its origins in someones unsubstantiated theory or guess or wishful thinking, and not in documented scientific evidence

    But by doing this you only allow a falsehoold to gain acceptance, often to the point where its considered a fundamental truth. And then people take that fundamental truth and go on to make further deductions and further theories based upon it.

    Eventually it turns into an ungodly tangled mess of misinformation and confusion. This has been a pet peeve of mine for years and years. It has been the source of me wanting to pull my hair out many a time
    I don't agree,or disagree....so where are these so called studies????...feel free to post a link.
    The LORD is my rock, my fortress, and my savior; my God is my rock, in whom I find protection. He is my shield, the power that saves me, and my place of safety.-Psalm 18:2
  6. Bananas
    Board Sponsor
    TripDog's Avatar
    Stats
    5'10"  201 lbs.
    Join Date
    Mar 2006
    Posts
    10,084
    Answers
    0


    good info tho!!
    The LORD is my rock, my fortress, and my savior; my God is my rock, in whom I find protection. He is my shield, the power that saves me, and my place of safety.-Psalm 18:2
  7. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by TripDog View Post
    I don't agree,or disagree....so where are these so called studies????...feel free to post a link.


    The following clearly support the notion that longR3 and other analogs of IGF-1 that bind poorly or not at all to IGF-1 binding proteins are cleared from the body quicker than regular IGF-1

    If you have studies that indicate the contrary please share. I am open minded


    Am J Physiol. 1999 Apr;276(4 Pt 1):E663-71. Links
    Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions.Robertson JG, Belford DA, Ballard FJ.
    Child Health Research Institute, North Adelaide, South Australia 5006.

    We have examined the role binding proteins have in regulating the clearance of exogenous growth factors from wounds. Hunt-Schilling chambers were subcutaneously implanted in rats, and the clearance of insulin-like growth factor (IGF) I from the chamber wound fluid was compared with IGF-II, LR3-IGF-I, which binds poorly to IGF-binding proteins (IGFBP), or insulin. Elimination rate constants of the slow phase of the decay curves did not differ between IGF-I and IGF-II. However, LR3-IGF-I and insulin were cleared more rapidly from wound fluid than IGF-I so that the half-lives for IGF-I, IGF-II, LR3-IGF-I, and insulin were 872, 861, 563, and 324 min, respectively. In wound fluid, minimal degradation of the IGFs occurred, whereas insulin was degraded considerably. The increased clearance of LR3-IGF-I and insulin equated with a reduced association with wound fluid IGFBPs, and increased amounts of radioactivity of these peptides were detected in the circulation and urine. These results show that this model of wound repair may be of use in examining the kinetics of growth factors and other bioactive molecules in extravascular spaces and support the hypothesis that IGFBPs can be significant regulators of IGF bioavailability in vivo.

    PMID: 10198302 [PubMed - indexed for MEDLINE]

    J Endocrinol. 1993 Aug;138(2):327-36. Links
    Plasma clearance and tissue distribution of labelled insulin-like growth factor-I (IGF-I) and an analogue LR3IGF-I in pregnant rats.Bastian SE, Walton PE, Wallace JC, Ballard FJ.
    Department of Biochemistry, University of Adelaide, South Australia.

    To determine whether the changes in insulin-like growth factor-binding proteins (IGFBPs) and IGF-I levels during pregnancy in rats affect the clearance of IGFs from the circulation, we have measured pharmacokinetic parameters and the tissue distribution of radiolabelled IGF-I and LR3IGF-I, a potent analogue which has a markedly reduced affinity of binding to the IGFBPs. Intravenous boluses of radiolabelled growth factors were administered to catheterized virgin and age-matched pregnant rats on day 18 of gestation when plasma IGFBPs, in particular IGFBP-3, are dramatically reduced. IGF-I was cleared more rapidly from plasma in pregnant rats compared with the virgins; metabolic clearance rate (MCR) = 2.88 +/- 0.12 (S.E.M.) and 0.90 +/- 0.05 ml/min per kg respectively. Although LR3IGF-I was cleared more rapidly than IGF-I from plasma, similar clearance rates for the analogue were obtained in both pregnant and virgin animals, MCR = 9.19 +/- 0.15 and 9.84 +/- 0.28 ml/min per kg respectively. In virgin rat plasma, labelled IGF-I was mainly associated with the 150 kDa complex, whereas in pregnant rat plasma IGF-I was predominantly associated with lower M(r) IGFBPs (approximately 30-50 kDa). The majority of LR3IGF-I was detected as free peptide. A larger proportion of the tracer was detected as small M(r) breakdown products in plasma from rats under conditions of reduced binding to IGFBPs, e.g. during pregnancy or when LR3IGF-I was the labelled tracer, suggesting greater rates of IGF degradation. More LR3IGF-I tracer was detected in kidneys, ovaries and adrenals of virgin rats and in the ovaries and adrenals of pregnant rats, compared with IGF-I tracer. IGF-I radioactivity was greater than LR3IGF-I in caecum, brain, liver and heart in virgin rats and in kidneys, caecum, brain, liver, heart, placenta, fetus and fetal plasma of the pregnant rats. These results show that the reduction in IGFBP during pregnancy dramatically increased the clearance of IGF-I from the circulation towards that obtained with LR3IGF-I. The observation that less LR3IGF-I was detected in placenta, fetus and fetal plasma compared with IGF-I raises the possibility that the ability to bind IGFBPs during pregnancy may enhance IGF uptake by the conceptus.

    PMID: 7693845 [PubMed - indexed for MEDLINE]

    J Endocrinol. 1997 Nov;155(2):377-86. Links
    IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys.Tomas FM, Walton PE, Dunshea FR, Ballard FJ.
    Cooperative Research Centre for Tissue Growth and Repair, Adelaide, South Australia, Australia.

    The relative acute hypoglycaemic potencies of IGF-I and several variants of IGF-I which bind poorly to the IGF-I binding proteins (IGFBPs) have been examined in marmosets (Callithrix jacchus) and the pig. In the marmoset study, IGF-I and des(1-3)IGF-I were compared in anaesthetised and conscious animals in a range of bolus doses from 42 to 270 micrograms/kg body weight. In the pig study, IGF-I was compared with four variants, des(1-3)IGF-I long-IGF-I, R3IGF-I and long-R3IGF-I (LR3IGF-I), which show reduced affinity for the IGFBPs as well as with insulin. Doses in the pig were 20 and 50 micrograms/kg body weight for the IGFs and 3 micrograms/kg for insulin. In each study serial blood samples were taken from 30 min before to 4 h after the bolus injection. Plasma glucose levels were decreased in a dose-responsive manner with the pig more sensitive than either the conscious or anaesthetised marmoset (maximum lowering 4.8, 3.7 and 2.5 mmol/l respectively). The IGF variants were consistently 2- to 3-fold more potent than IGF-I in each animal for lowering of plasma glucose to the nadir, with the potency reflecting the relative affinities for binding to the IGFBPs and the IGF-I receptors. Thus, hypoglycaemic potency was in the order IGF-I < long-IGF-I < R3IGF-I approximately LR3IGF-I < des (1-3)IGF-I. Notably the variants suppressed plasma glucose levels over a much longer period than did IGF-I, the cumulative suppression over four hours showing an approximately 4- to 8-fold increase in the extent of hypoglycaemia. The prolonged suppression was not simply proportional to the hypoglycaemic nadir; at doses equipotent for glucose lowering, the cumulative hypoglycaemic effect for the variants in either species was about 2-fold that for IGF-I. The differential effect of the variants in the marmoset could not be accounted for by correlated changes in plasma insulin, IGF-I or IGFBP levels in plasma. Indirect effects via inhibition of glucagon, or direct effects via hepatic insulin receptors are postulated to account for the results. There was a dose-related reduction in plasma amino acids in the pig but, unlike the case for plasma glucose, only one analogue, LR3IGF-I was more potent than IGF-I. The response to LR3IGF-I was accentuated at the high dosage but on the basis of the other variants tested this effect could not be ascribed to either of the incorporated molecular variations. Despite their more rapid clearance from the circulation, variants of IGF-I which show lower affinity for binding to IGFBPs show proportionately superior potency for sustained hypoglycaemic action. Since our data were obtained in animal models of accepted relevance to humans these results point to the possible superior efficacy of the variants, especially des(1-3)IGF-I, over IGF-I for use as an adjunct to insulin treatment of hyperglycaemic conditions.

    PMID: 9415072 [PubMed - indexed for MEDLINE]
  8. Bananas
    Board Sponsor
    TripDog's Avatar
    Stats
    5'10"  201 lbs.
    Join Date
    Mar 2006
    Posts
    10,084
    Answers
    0


    Quote Originally Posted by Patrick Arnold View Post
    The following clearly support the notion that longR3 and other analogs of IGF-1 that bind poorly or not at all to IGF-1 binding proteins are cleared from the body quicker than regular IGF-1

    If you have studies that indicate the contrary please share. I am open minded


    Am J Physiol. 1999 Apr;276(4 Pt 1):E663-71. Links
    Clearance of IGFs and insulin from wounds: effect of IGF-binding protein interactions.Robertson JG, Belford DA, Ballard FJ.
    Child Health Research Institute, North Adelaide, South Australia 5006.

    We have examined the role binding proteins have in regulating the clearance of exogenous growth factors from wounds. Hunt-Schilling chambers were subcutaneously implanted in rats, and the clearance of insulin-like growth factor (IGF) I from the chamber wound fluid was compared with IGF-II, LR3-IGF-I, which binds poorly to IGF-binding proteins (IGFBP), or insulin. Elimination rate constants of the slow phase of the decay curves did not differ between IGF-I and IGF-II. However, LR3-IGF-I and insulin were cleared more rapidly from wound fluid than IGF-I so that the half-lives for IGF-I, IGF-II, LR3-IGF-I, and insulin were 872, 861, 563, and 324 min, respectively. In wound fluid, minimal degradation of the IGFs occurred, whereas insulin was degraded considerably. The increased clearance of LR3-IGF-I and insulin equated with a reduced association with wound fluid IGFBPs, and increased amounts of radioactivity of these peptides were detected in the circulation and urine. These results show that this model of wound repair may be of use in examining the kinetics of growth factors and other bioactive molecules in extravascular spaces and support the hypothesis that IGFBPs can be significant regulators of IGF bioavailability in vivo.

    PMID: 10198302 [PubMed - indexed for MEDLINE]

    J Endocrinol. 1993 Aug;138(2):327-36. Links
    Plasma clearance and tissue distribution of labelled insulin-like growth factor-I (IGF-I) and an analogue LR3IGF-I in pregnant rats.Bastian SE, Walton PE, Wallace JC, Ballard FJ.
    Department of Biochemistry, University of Adelaide, South Australia.

    To determine whether the changes in insulin-like growth factor-binding proteins (IGFBPs) and IGF-I levels during pregnancy in rats affect the clearance of IGFs from the circulation, we have measured pharmacokinetic parameters and the tissue distribution of radiolabelled IGF-I and LR3IGF-I, a potent analogue which has a markedly reduced affinity of binding to the IGFBPs. Intravenous boluses of radiolabelled growth factors were administered to catheterized virgin and age-matched pregnant rats on day 18 of gestation when plasma IGFBPs, in particular IGFBP-3, are dramatically reduced. IGF-I was cleared more rapidly from plasma in pregnant rats compared with the virgins; metabolic clearance rate (MCR) = 2.88 +/- 0.12 (S.E.M.) and 0.90 +/- 0.05 ml/min per kg respectively. Although LR3IGF-I was cleared more rapidly than IGF-I from plasma, similar clearance rates for the analogue were obtained in both pregnant and virgin animals, MCR = 9.19 +/- 0.15 and 9.84 +/- 0.28 ml/min per kg respectively. In virgin rat plasma, labelled IGF-I was mainly associated with the 150 kDa complex, whereas in pregnant rat plasma IGF-I was predominantly associated with lower M(r) IGFBPs (approximately 30-50 kDa). The majority of LR3IGF-I was detected as free peptide. A larger proportion of the tracer was detected as small M(r) breakdown products in plasma from rats under conditions of reduced binding to IGFBPs, e.g. during pregnancy or when LR3IGF-I was the labelled tracer, suggesting greater rates of IGF degradation. More LR3IGF-I tracer was detected in kidneys, ovaries and adrenals of virgin rats and in the ovaries and adrenals of pregnant rats, compared with IGF-I tracer. IGF-I radioactivity was greater than LR3IGF-I in caecum, brain, liver and heart in virgin rats and in kidneys, caecum, brain, liver, heart, placenta, fetus and fetal plasma of the pregnant rats. These results show that the reduction in IGFBP during pregnancy dramatically increased the clearance of IGF-I from the circulation towards that obtained with LR3IGF-I. The observation that less LR3IGF-I was detected in placenta, fetus and fetal plasma compared with IGF-I raises the possibility that the ability to bind IGFBPs during pregnancy may enhance IGF uptake by the conceptus.

    PMID: 7693845 [PubMed - indexed for MEDLINE]

    J Endocrinol. 1997 Nov;155(2):377-86. Links
    IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys.Tomas FM, Walton PE, Dunshea FR, Ballard FJ.
    Cooperative Research Centre for Tissue Growth and Repair, Adelaide, South Australia, Australia.

    The relative acute hypoglycaemic potencies of IGF-I and several variants of IGF-I which bind poorly to the IGF-I binding proteins (IGFBPs) have been examined in marmosets (Callithrix jacchus) and the pig. In the marmoset study, IGF-I and des(1-3)IGF-I were compared in anaesthetised and conscious animals in a range of bolus doses from 42 to 270 micrograms/kg body weight. In the pig study, IGF-I was compared with four variants, des(1-3)IGF-I long-IGF-I, R3IGF-I and long-R3IGF-I (LR3IGF-I), which show reduced affinity for the IGFBPs as well as with insulin. Doses in the pig were 20 and 50 micrograms/kg body weight for the IGFs and 3 micrograms/kg for insulin. In each study serial blood samples were taken from 30 min before to 4 h after the bolus injection. Plasma glucose levels were decreased in a dose-responsive manner with the pig more sensitive than either the conscious or anaesthetised marmoset (maximum lowering 4.8, 3.7 and 2.5 mmol/l respectively). The IGF variants were consistently 2- to 3-fold more potent than IGF-I in each animal for lowering of plasma glucose to the nadir, with the potency reflecting the relative affinities for binding to the IGFBPs and the IGF-I receptors. Thus, hypoglycaemic potency was in the order IGF-I < long-IGF-I < R3IGF-I approximately LR3IGF-I < des (1-3)IGF-I. Notably the variants suppressed plasma glucose levels over a much longer period than did IGF-I, the cumulative suppression over four hours showing an approximately 4- to 8-fold increase in the extent of hypoglycaemia. The prolonged suppression was not simply proportional to the hypoglycaemic nadir; at doses equipotent for glucose lowering, the cumulative hypoglycaemic effect for the variants in either species was about 2-fold that for IGF-I. The differential effect of the variants in the marmoset could not be accounted for by correlated changes in plasma insulin, IGF-I or IGFBP levels in plasma. Indirect effects via inhibition of glucagon, or direct effects via hepatic insulin receptors are postulated to account for the results. There was a dose-related reduction in plasma amino acids in the pig but, unlike the case for plasma glucose, only one analogue, LR3IGF-I was more potent than IGF-I. The response to LR3IGF-I was accentuated at the high dosage but on the basis of the other variants tested this effect could not be ascribed to either of the incorporated molecular variations. Despite their more rapid clearance from the circulation, variants of IGF-I which show lower affinity for binding to IGFBPs show proportionately superior potency for sustained hypoglycaemic action. Since our data were obtained in animal models of accepted relevance to humans these results point to the possible superior efficacy of the variants, especially des(1-3)IGF-I, over IGF-I for use as an adjunct to insulin treatment of hyperglycaemic conditions.

    PMID: 9415072 [PubMed - indexed for MEDLINE]
    Great post bro.....i love reading this sh!t
    The LORD is my rock, my fortress, and my savior; my God is my rock, in whom I find protection. He is my shield, the power that saves me, and my place of safety.-Psalm 18:2
  9. Bananas
    Board Sponsor
    TripDog's Avatar
    Stats
    5'10"  201 lbs.
    Join Date
    Mar 2006
    Posts
    10,084
    Answers
    0


    Quote Originally Posted by Jayhawkk View Post
    Seems in this industry just give it time and everything will swing 180 degrees. It's like the Culture Club all over again.
    good point tho Jay....seems to be the way it goes...here's a burger for ya
    The LORD is my rock, my fortress, and my savior; my God is my rock, in whom I find protection. He is my shield, the power that saves me, and my place of safety.-Psalm 18:2
  10. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by TripDog View Post
    Great post bro.....i love reading this sh!t
    good cuz the relevant information was hidden in each of these articles and takes careful reading to recognize and understand it. I assume you did
  11. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by Patrick Arnold View Post
    However, LR3-IGF-I and insulin were cleared more rapidly from wound fluid than IGF-I so that the half-lives for IGF-I, IGF-II, LR3-IGF-I, and insulin were 872, 861, 563, and 324 min, respectively.

    Although LR3IGF-I was cleared more rapidly than IGF-I from plasma, similar clearance rates for the analogue were obtained in both pregnant and virgin animals, MCR = 9.19 +/- 0.15 and 9.84 +/- 0.28 ml/min per kg respectively.


    Despite their more rapid clearance from the circulation, variants of IGF-I which show lower affinity for binding to IGFBPs show proportionately superior potency for sustained hypoglycaemic action.

    here are the relevant passages isolated for easier consumption
  12. Registered User
    jenab123's Avatar
    Join Date
    Jun 2003
    Posts
    53
    Answers
    0


    Quote Originally Posted by Patrick Arnold View Post
    here are the relevant passages isolated for easier consumption
    What does all this mean in terms of what we care about: adding muscle? It is not clear to me that the fraction of bound IGF1 that eventually does what we want it to do is more useful in that regard than all the unbound LR3IGF1 floating around.
  13. Banned
    jomi822's Avatar
    Join Date
    Jul 2005
    Age
    32
    Posts
    2,419
    Answers
    0


    i am sure the study is accurate, but how does this translate into dosing and time considerations from a bodybuilders perspective?

    anyone that has used igf-1lr3 can attest to the fact that the stuff lasts a good 2-3 days having some kidn of affect on the body. Intracellular mediated?
  14. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by jenab123 View Post
    What does all this mean in terms of what we care about: adding muscle? It is not clear to me that the fraction of bound IGF1 that eventually does what we want it to do is more useful in that regard than all the unbound LR3IGF1 floating around.
    it is not clear to me either. what is clear is that hypoglycemia is more of a concern.
  15. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by jomi822 View Post
    i am sure the study is accurate, but how does this translate into dosing and time considerations from a bodybuilders perspective?

    anyone that has used igf-1lr3 can attest to the fact that the stuff lasts a good 2-3 days having some kidn of affect on the body. Intracellular mediated?
    certainly the physiological effects can continue to manifest well after the compound is cleared from the system. the same is true for anabolic steroids. the hormones simply intiate cellular responses which will continue to carry out their function for some time after the genes are activated by the receptor/hormone complex
  16. Banned
    jomi822's Avatar
    Join Date
    Jul 2005
    Age
    32
    Posts
    2,419
    Answers
    0


    so in short, bodybuilders assumed the drug was active for such a long time because of the intracellular events that continued after the drug cleared the system.

    igf-1 lr3 actually has a shorter half life than regular igf-1 because it is not able to bind to protective proteins, but produces a much stronger response that can last for days?

    word PA

    im sure it helps to pump 20-40 times more than the bodies natural levels of igf-1 into the system, on top of it just being a stronger peptide.
  17. Registered User
    jenab123's Avatar
    Join Date
    Jun 2003
    Posts
    53
    Answers
    0


    Quote Originally Posted by jomi822 View Post
    so in short, bodybuilders assumed the drug was active for such a long time because of the intracellular events that continued after the drug cleared the system.
    Or that they simply felt hypoglycemic for a very long time, which alone could also have other anabolic effects downstream, especially if you ate lots of carbs.
  18. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by jomi822 View Post
    so in short, bodybuilders assumed the drug was active for such a long time because of the intracellular events that continued after the drug cleared the system.

    igf-1 lr3 actually has a shorter half life than regular igf-1 because it is not able to bind to protective proteins, but produces a much stronger response that can last for days?

    word PA

    im sure it helps to pump 20-40 times more than the bodies natural levels of igf-1 into the system, on top of it just being a stronger peptide.

    It produces a stronger hypoglycemic response than IGF-1 that lasts for a long time. Thats all you can deduce from the studies here

    How much more effective it is than regular IGF-1 in regards to anabolism in humans is not so clear cut. The data available is only really on animals and even that is inconsistent. In fact, in pigs its been shown to be catabolic in a study and anabolic in another. And since it is delivered by infusion instead of by bolus injections (as athletes use it) comparisons are even more difficult to make

    Br J Nutr. 2002 Jun;87(6):587-93. Links
    Insulin-like growth factor-I and analogues increase growth in artificially-reared neonatal pigs.Dunshea FR, Chung CS, Owens PC, Ballard JF, Walton PE.
    Victorian Institute of Animal Science, 600 Sneydes Rd., Werribee, Australia. Frank.Dunshea@nre.vic.gov.au

    Exogenous insulin-like growth factor (IGF)-I has been shown to increase growth rate in neonatal pigs while an analogue of IGF-I, long arginine (LR3) IGF-I, has been shown to be more potent than IGF-I in the rat. Therefore, two studies were conducted to determine whether IGF-I and LR3IGF-I increase growth in the artificially-reared neonatal pig. Expt 1 involved forty-two (2 kg initial weight) pigs infused with either control, IGF-I (2, 4 or 8 microg/h) or LR3IGF-I (2, 4 or 8 microg/h) infusions for 8 d. Pigs were weighed and then offered 1.7 MJ (gross energy) milk replacer/kg0.75 per d. Expt 2 involved eighteen pigs (2 kg initial weight) treated with control saline, IGF-I (8 microg/h) or LR3IGF-I (8 microg/h) infusions. After 9 d an additional pump was inserted to increase the infusion rates of each of the growth factors (16 microg/h) for a further 9 d. Cows' milk was provided ad libitum. In Expt 1 there was no overall effect of growth factors on daily weight gain or slaughter weight. However, milk intake was greater in pigs infused with growth factors (909 v. 867 g/d, P=0.027), with an apparently greater milk intake by the pigs infused with IGF-I compared with LR3IGF-I (920 v. 898 g/d, P=0.12). Infusion of LR3IGF-I decreased plasma IGF-I concentrations, but had no effect on plasma IGF-II concentrations. In Expt 2, neither IGF-I nor LR3IGF-I infusion had any effect upon daily weight gain over the first 9 d of the study. However, over the second 9 d of the study, daily weight gain was increased in LR3IGF-I-infused pigs (457 v. 386 g/d, P<0.01), but not in pigs infused with IGF-I (413 v. 386 g/d, P=0.15). Milk intake was not different during the first 9 d of the study but was significantly greater in pigs infused with growth factors over the second half of the study (3407 v. 2905 g/d, P<0.01). Plasma IGF-binding protein-3 concentrations were highly correlated (R=0.85) with average daily gain over the 3 d preceding blood sampling. In conclusion, exogenous IGF-I and particularly LR3IGF-I can increase growth rate and milk intake in artificially-reared pigs fed ad libitum but not in limit-fed piglets.

    -------------

    J Endocrinol. 1997 Dec;155(3):559-65. Links
    Long [R3] insulin-like growth factor-I reduces growth, plasma growth hormone, IGF binding protein-3 and endogenous IGF-I concentrations in pigs.Dunaiski V, Dunshea FR, Walton PE, Goddard C.
    Cooperative Research Centre for Tissue Growth and Repair, Adelaide, South Australia, Australia.

    Growth hormone (GH) improves growth performance in the pig. Analogues of insulin-like growth factor-I (IGF-I) that bind poorly to IGF binding proteins (IGFBP) stimulate growth in the rat but, in contrast, inhibit growth in the pig. This study was designed to determine the effect of IGF peptides alone or in combination with porcine GH (pGH) on growth characteristics and plasma hormone concentrations in finisher pigs. A four-day infusion of Long [R3] IGF-I (LR3IGF-I; 180 micrograms/kg/day) decreased the average daily gain, food intake, and plasma IGFBP-3, IGF-I and insulin concentrations. The mean plasma GH concentration was decreased by 23% and the area under the GH peaks was reduced by 60%. Co-administration of pGH (30 micrograms/kg/day) with LR3IGF-I had no interactive effect on growth performance, and plasma insulin, IGFBP-3 and IGF-I concentrations remained suppressed. The area under the GH peaks was not restored with this combination treatment although mean plasma GH concentrations were elevated in all animals receiving pGH. Infusion of IGF-I (180 micrograms/kg/day) decreased plasma insulin and mean GH concentrations but had no significant effect on IGFBP-3 concentrations. Average daily gain and feed intake were not changed by IGF-I treatment. A combination of IGF-I and pGH injection (30 micrograms/kg/day) increased plasma IGFBP-3 concentrations but plasma insulin levels remained suppressed. Plasma glucose levels were unaffected by any treatment. The study demonstrates that both IGF-I and LR3IGF-I suppress plasma GH concentrations in finisher pigs. This, in turn, may be responsible for the reduction in the plasma concentration of IGF-I, IGFBP-3 and insulin seen in LR3IGF-I-treated animals. The decrease in these parameters may contribute to the inhibitory effect of LR3IGF-I on growth performance in the pig.
  19. Registered User
    MANotaur's Avatar
    Stats
    6'1"  210 lbs.
    Join Date
    Dec 2012
    Posts
    2,393
    Answers
    0


    PA clear messages please! i know this is a dead thread but i figure any is good as the others
    Quote Originally Posted by iparatroop View Post
    I'm usually crying when people take naked pictures of me. Fcuking childhood.
  20. Featured Author
    Patrick Arnold's Avatar
    Join Date
    Apr 2007
    Posts
    4,119
    Answers
    0


    Quote Originally Posted by MANotaur View Post
    PA clear messages please! i know this is a dead thread but i figure any is good as the others
    cleared
    Anabolicminds.com Featured Author
  •   

      
     

Similar Forum Threads

  1. How long is the half life of Anastrozole (liquidex)
    By b4554 in forum Male Anti-Aging Medicine
    Replies: 26
    Last Post: 02-12-2010, 02:57 PM
  2. whats the half life of trimax
    By bigrich954rr in forum Supplements
    Replies: 0
    Last Post: 06-18-2005, 02:24 PM
  3. whats the half life of tren and test pro
    By bigrich954rr in forum Anabolics
    Replies: 4
    Last Post: 05-22-2005, 09:41 PM
  4. What's The Half Life Of T3?
    By TheMyth in forum Anabolics
    Replies: 3
    Last Post: 03-16-2005, 11:24 AM
  5. whats the half life of 1-test cyp
    By BigRich in forum Anabolics
    Replies: 20
    Last Post: 08-31-2004, 05:43 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in