Why it's Worth Combining IGF-1 and GH

[CatDaddy]

Good read on combining IGF-1 and GH, not a ton of info or research but nonetheless it makes sense.

"Why it's worth combining IGF-1 and GH

It would of course be expensive, but in theory there's a lot to be said for combining growth hormone [structure shown below] and IGF-1, writes the Dutch endocrinologist Joop Janssen in an article in Reviews in Endocrine Metabolic Disorders. The article is worth looking at if you're a chemical athlete.

Human Growth Hormone

The first argument that Janssen comes up with is that IGF-1 remains active for longer in the body if you inject it in combination with growth hormone. This is because IGF-1 is active for longer if it is attached to the binding protein IGFBP3. If you inject IGF-1 on its own, the production of this binding protein goes down. But if you inject growth hormone and IGF-1 together, the concentration of this binding protein increases. That might mean that you would have to inject less frequently, as IGF-1 breaks down quickly in the body.

A second argument is that growth hormone makes the cells 'ignore' insulin. As a result, blood sugar levels rise, as does the insulin level. In the long run this might not be so beneficial to health, and it would inhibit muscle growth. If you use IGF-1 together with growth hormone, then the muscle cells become more sensitive to insulin. And that would mean more muscle protein build-up.

Why it's worth combining IGF-1 and GH

The advantage of combining IGF-1 and GH is also a potential disadvantage, according to Janssen. On a molecular level the same processes involved in muscle growth are also found in cancer cells and tumours. The combination of both hormones might therefore give any tumours a growth stimulus. The same applies to other side effects such as undesirable growth of the jawbone, headache and trapped nerves in the hands.
In the final section of the article, the endocrinologist stresses that there have been very few studies on the effect of combined administration of GH and IGF-1, and that his article is mainly theoretical. "Determination of whether coadministration of GH and IGF-I is indeed superior to GH alone or IGF-I alone awaits further study", concludes Janssen.

Source:
Rev Endocr Metab Disord. 2009 Jun;10(2):157-62.



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[SoonerClint72]

Nice...thanks for the post.

Sooner

 

[Sciroxx]

Few remarks with your permission

1. IGF1 and GH are binding to completely different proteins (carriers), and both GH and IGF1 dont effect on the other's binding proteins

2. IGF1-lr3 which is the commonly used exogenous IGF1 is resistant to the IGF1-binding proteins, this is why he has such a long half life as well
For a brief explanation (refer to Insulin-like growth factor-I analogue protects muscles of dystrophic mdx mice from contraction-mediated damage. - PubMed - NCBI ) - The actions of IGF-I in vivo are modulated by IGF binding proteins (IGFBPs), which generally act to inhibit IGF-I signalling. the analogue of IGF-I (LR IGF-I) has a significantly reduced binding affinity for IGFBPs

3. You raised an important sunject of insuin sensitivity, I'll specify a bit - GH is a stress hormone, as such it raises glucose serum levels, when glucose levels rise the body seretes insulin to balance the glucse levels, easy ..... BUT when one uses high exogenous high dosages of GH the glucose levels rise sharply, when this phenomena happens over time the body keeps high insulin leves around the clock, which lowers nsulin sensitivity, this leads over long abuse to diabetics. IGF actually counter this effect and help keeping optimal insuin sensitivity

Here are a couple o articles to specify more and support this post -

ncbi.nlm.nih.gov/pubmed/8853443 GH may exert metabolic effects either directly or indirectly through increased production of IGF-I. GH administration increases circulating IGF-I levels via stimulation of hepatic synthesis and secretion of IGF-I; it may also enhance local IGF-I synthesis, which exerts paracrine or autocrine effects. Figure 2 summarizes the metabolic effects of GH and IGF-I. Administration of GH and IGF-I in adult humans has been demonstrated to enhance protein anabolism. Combined administration of GH and IGF-I was observed to be more anabolic than either IGF-I or GH alone. Evidence is presented that protein accretion results mainly from direct effects of GH on tissues; additional indirect effects via IGF-I production are also likely. Administration of GH has been reported to produce carbohydrate intolerance with elevated plasma insulin levels, resulting from insulin resistance. in contrast, insulin sensitivity increased during administration of IGF-I, which exerts hypoglycaemic effects even with concomitant suppression of insulin secretion. A major direct metabolic effect of GH is to increase fat mobilization and oxidation, and thereby to reduce total body fat; there is no evidence that IGF-I acts directly on adipose tissue in vivo. GH administration results in sodium retention via stimulation of Na-K-ATPase. It is suggested that part of the effects of GH on tubular function (e.g. phosphate reabsorption) are mediated via IGF-I. Energy expenditure may be increased by administration of either GH or relatively high doses of IGF-I. One of the reasons for this phenomenon is an increase in lean body mass; GH may increase energy expenditure additionally be enhancing the production of T3 and by increasing lipid oxidation

 

[CatDaddy]

Thank you for the additional info [MENTION=698]Sciroxx[/MENTION]


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