Talk:Insulin-like growth factor 1
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What about IGF-2? can somebody elaborate on this?
IGF-2 is a naturally occuring second protein, related to IGF-1. It binds the IGF1 receptor at somewhat lower affinity than IGF1. Both IGF1 and IGF2 can induce growth in the animal via the IGF1 receptor. Gacggt 21:46, 26 July 2006 (UTC)
[edit] long r3 igf-1
The most effective (artifically modified) 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.” The only two IGF-1 Long R3 brands available on the market today are Revitropin and Igtropin. There is also a [[black market] for it with an average price of $150/1mg. This black market is especially used by [bodybuilders] and [athletes] who want to increase their lean body mass.
I removed the above temporarily for a couple of reasons. The reader will think this is simply another tested and approved IGF1 or somatropin product when it is deliberately being marketed as an "offshore" pharmaceutical for "experimental" use, which in plain language means they have not demonstrated efficacy or safety to any qualified agency, and they want to sell it without oversight, without liability or legal recourse for the buyer. This needs to be made excruciatinly clear. For those who mistrust "Big Pharma" the only thing potentially worse is a situation like this. The second problem is that statements about the effectiveness of a product like this need references. If there are no published papers about this compound, it does not belong here. Thanks for understanding. alteripse 01:01, 14 May 2006 (UTC)
[edit] IGF-1 and lifespan
I've heard that IGF-1 also interacts with lifespan; invertebrates with deficient IGF-1 receptors have a longer lifespan. However, low levels of IGF-1 in older human adults seems is linked with a shorter lifespan. —The preceding unsigned comment was added by Bayle Shanks (talk • contribs) 04:29, 12 December 2006 (UTC).
See for example http://dx.doi.org/10.1007/s00018-004-4297-y Bayle Shanks 04:31, 12 December 2006 (UTC)
There is indeed some record of increased lifespan in the (partial) absence of IGF-1 receptors (and consequently: reduced IGF-1 signaling). [Paper: IGF-1 receptor regulates lifespan and resistance to oxidative stress in mice.]. You have to see the bigger picture as well however, increased life-span doesn't mean staying young, nor does it mean that there are no other harmfull effects, this particular article only addresses life-span & resistance to oxidative stress in mice. Mice are quite different from men, they are short-lived high breeders (high predator pressure), while we are long-lived, slow breeders. Mechanisms that influence lifespan can thus be expected to have different effects in mice versus humans. Daviddecraene 08:03, 12 December 2006 (UTC)