HOW LONG IS LR3-IGF1ACTIVE ?
- 02-09-2005, 06:47 PM
- 02-09-2005, 06:50 PM
02-09-2005, 06:56 PM
I have HEARD FROM 10-12 HOURS, BUT LOOK AT THE stiCKIES... HERES an excerpt! (just messing with you about the caps,lol)
"The most effective form of IGF is Long R3 IGF-1, it has been chemically altered and has had amino acid changes which cause it to avoid binding to proteins in the human body and allow it to have a much longer half life, around 20-30 hours. "Long R3 IGF-1 is an 83 amino acid analog of IGF-1 comprising the complete human IGF-1 sequence with the substition of an Arg(R) for the Glu(E) at position three, hence R3, and a 13 amino acid extension peptide at the N terminus. This analog of IGF-1 has been produced with the purpose of increasing the biological activity of the IGF peptide."
02-09-2005, 07:09 PM
thanks grant , i relized i had the caps on after i keyed that whole thing, i still hunt and peck with one hand so i just didnt want to key it all over[lazy],"LOL" ...but i thought i read it was more like 10-12 hours.
02-09-2005, 07:36 PM
02-11-2005, 12:30 AM
LR3IGF-1 is actually cleared form plasma faster than IGF-1. Plasma clearance however does not speak of receptor binding strength, which is where LR3IGF-1 retains is potency of IGF-1.
10-12 hours is just a ridiculous statement most likely originating from a person selling the product (doesn't speak highly of their product knowledge) or an idiot.
Growth Regul. 1993 Mar;3(1):40-4.
Effects of interactions between IGFBPs and IGFs on the plasma clearance and in vivo biological activities of IGFs and IGF analogs.
Ballard FJ, Walton PE, Bastian S, Tomas FM, Wallace JC, Francis GL.
Cooperative Research Centre for Tissue Growth and Repair, Adelaide, Australia.
The relative activities in vivo of IGFs that differ in their association affinities towards IGF binding proteins (IGFBPs) have been examined in a series of comparisons between IGF-I and LR3IGF-I. IGF-I has approximately 1000 fold higher affinity than LR3IGF-I towards IGFBP-3, IGFBP-4, total rat plasma IGFBPs and L6 myoblast BP. In cultured L6 myoblasts the reduced association with IGFBPs gives LR3IGF-I a 5-10 fold greater biological potency. Chronic administration of the peptides over 14 days to normal female rats produces marked increases in body weight, nitrogen retention and food conversion efficiency as well as retention of the carcass composition and fractional weights of the gut, spleen and thymus that are characteristic of the younger age. In the growth measurements LR3IGF-I is 6 fold more potent than IGF-I, thus reflecting the in vitro difference. In a second series of experiments in which the clearance rates of the two peptides were compared, LR3IGF-I was shown to be removed from the plasma much more rapidly than was IGF-I, a difference reflecting the poor association of LR3IGF-I with plasma IGFBPs. The crucial relevance of binding protein association in explaining the difference was confirmed in pregnant rats where IGFBP levels are markedly reduced. In this condition only the clearance of IGF-I was affected to produce a clearance rate almost as rapid as that found with LR3IGF-I. These experiments demonstrate that an IGF variant which associates poorly with IGFBPs is removed more rapidly from the blood and is more potent than IGF-I.
J Endocrinol. 1996 Jul;150(1):77-84.
Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection.
Tomas FM, Lemmey AB, Read LC, Ballard FJ.
Cooperative Research Centre for Tissue Growth and Repair, CSIRO Division of Human Nutrition, Adelaide, South Australia, Australia.
The relative potency of IGF-I and the analogue LR3IGF-I to either promote growth or reverse catabolism in rats when administered by injection rather than by continuous infusion has been examined. LR3IGF-I has very low affinity for the IGF-binding proteins in the rat and hence is cleared from the circulation more quickly than is IGF-I. Experiments were performed in normal growing rats (150 g body weight) and in rats made catabolic by dexamethasone infusion (20 micrograms/day). IGFs or vehicle were delivered subcutaneously for 7 days either by continuous infusion via osmotic pumps or by injection once or twice daily at 320 and 400 micrograms/day in normal and catabolic rats respectively. As expected, continuous infusion of IGFs showed greater efficacy than either of the injection modes especially in its anti-catabolic actions. When infused continuously LR3IGF-I was generally 1.5- to 2-fold more potent than IGF-I for changes in body weight gain, visceral organ weights and feed use efficiency. Notably, LR3IGF-I remained more potent than IGF-I in several of these effects even when the peptides were given by once-daily injection. In addition, N tau-methylhistidine excretion by dexamethasone-treated rats was reduced to a threefold greater extent by injected LR3IGF-I than by injected IGF-I. Notwithstanding these effects, LR3IGF-I was barely equipotent with IGF-I for reversal of carcass muscle loss in dexamethasone-treated rats. Despite its more rapid clearance from the circulation, injected LR3IGF-I retains superior potency to injected IGF-I for several actions, albeit the potency is much reduced compared with continuous infusion. Thus our data indicate that use of IGF analogues which have low affinity for binding proteins may have advantages in potency and/or tissue specificity where IGFs are necessarily administered by injection.
02-11-2005, 02:25 AM
Incorrect, please read the sticky posted by Bobo on LR3IGF-1. It has current, relevant information that has been discovered since your abstracts were written in 1993 & 1996. FYI, the half-life of LR3IGF-1 is 20+ hours, mainly due to the fact it doesn't bind to the IGF binding proteins to get removed from the endocrine system and remains biologically active to exert its effects.Originally Posted by Jack Smack
02-12-2005, 01:19 AM
Originally Posted by gobig1
I do not see a sticky for LR3. I read the IGF-1 sticky and did not see any information related to LR3 having a 20+ hour half life. Care to back up your statement with some evidence?
BTW, I belive you have the wrong idea as to the biological role of IGFBPs. The do not speed plasma clearance of IGFs. BPs actually delay metabolism of the IGF so that when disassociated from the BP, IGF can bind to receptors. Without BPs providing a buffer of the IGF peptide, metabolism would occur so rapidly that the end biological result in terms of receptor activation would be nearly nill.
02-12-2005, 01:26 AM
http://www.anabolicminds.com/forum/s...ad.php?t=13470Originally Posted by Jack Smack
Jack, not trying to argue and I am by no means an expert on the subject, but I am currently on my 3rd cycle with LR3IGF-1, and without a doubt, the half life is probably fairly accurate at 20 hrs, give or take a couple. Also, my understanding is that the molecular change that makes it the "Long" version, makes it so it Doesn't bind to the IGF BP, thus making the half life as long as it is.
02-14-2005, 12:32 AM
Originally Posted by gobig1
That is the thread that I read and I can find nothing about 20 hours. The half life is not 20 hours. You are correct when you say that the N-terminus extension (coupled with the Arg substitution at postion 3) help to reduce affinity to BPs and reduce the rate of enzymatic degradation. However that that that severs to do is allow the peptide to be cleared from the plasma very rapidly.
What makes LR3IGF-1 a better growth propmtor as compared to IGF-1 is the strength to which it binds to the IGF-1 receptor (IGF-1r). The better growth promoting capabilites of LR3IGF-1 has absolutely nothign to do with an extended half life (which it doesn't have). Binding more tightly to the IGF-1r results more of the receptor specific activity is occuring and a higher amount of downstream signaling. The binding of the ligand to the receptor is only the first of many steps which then happen within the cell to results ultimately in tissue growth.
02-16-2005, 03:20 AM
Jack, here is the excerpt from the sticky, it is post #3 of this thread.Originally Posted by Grant
As in my life philosophy, I try to keep things simple as I don't have the time to do extensive research, that is why I love this board, others do have the time and contribute/share that information, AM is great.
Anectdotally speaking from my real world experience(s) it is longer than 10-12 hours. Not sure I am following you with the "binding" action. If a molecule is "bound" to a binding protein it becomes biologically inactive and unable to exert its desired effects, i.e., test vs free-test (bound-unbound).
Oh well, it works when I'm on it and that is good enough for me.
02-16-2005, 04:02 AM
You are going to accept what someone wrote arbitrarily without providing any references to validate the statment over the peer reviewed abstracts that I posted? YIKES BUD.
No one is arguing over the effectiveness of LR3IGF-1. What I am trying to point out to you the the true why in which the molecule exerts is action on the body.
Binding of a IGF-1 to an IGFBP does not mean elimination from the body, far from it. The BP protects the peptide from enzymartic degradtion (metabolism). Over the course of a period of time (diffeent for differnt BPs and molecules) the BP will disassociate from the peptide (for various reasons) allowing the peptide to bind to a receptor. New research is showing that IGFBPs, 6 of them I believe, when bound to IGF-1 have important biological functions and are not just inert. This is precisely why LR3, which does not bind well to IGFBPs, is cleared from the plasma so quickly.
LR3 is also protected from enzymatic degradation due to its amino acid substitutions and has a stronger binding affinity to the IGF-1r which is what produces the better growth we all see when administering LR3.
What you are feeling is NOT the half life of LR3, you are feeling the cascaed of effects that LR3 induces after binding to the IGF-1 receptor. Think of it as rolling a ball down a hill with several objects lined up in a path. The ball hits object 1 (this is L3 binding to receptor), then object 1 hit object 2 (the is the receptor/ligand complex interacting with various cellular proteins), object 2 hits object 3 (this is the proteins doing the various tasks that they are programmed to do with in the cell). Do you follow the picture now? That was a VERY simplifed analogy bt the way.
02-17-2005, 01:34 AM
Short answer......No, just like how I give little worth to your arbitrary keystrokes as well. I come to this board to learn, not argue.Originally Posted by Jack Smack
Have you even used LR3IGF-1? If not, you shouldn't be writing anything yourself concerning the subject. Try a little "real world" theoretical research instead of providing your own rhetoric cliff notes of someone's 20 year old research project.
I fully understand the cascade effects of the endocrine system.........back to the point please; this thread was simply based on "what is the half-life of LR3IGF-1?"
I say 20 hrs, you say 10 hrs, have a nice day.
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