Have been studying this interesting article:
Regulation of muscle mass by growth hormone and IGF-I
Would like to discuss in forum some of the conclusions.
"The use of GH in amateur and professional sports seems to be widespread, although the evidence is quite strong that supraphysiological GH administration does not potentiate the effects of exercise on muscle mass and strength in healthy individuals. IGF-I use is probably more limited as it is less readily available than GH."
"The attraction of GH abuse may be due to several reasons (Rennie, 2003; Rigamonti et al., 2005; Saugy et al., 2006; Gibney et al., 2007). First, GH is lipolytic although this benefit may not always be evident in well-trained athletes with low body fat (Deyssig et al., 1993). Second, GH has known effects on collagen and bone turnover and it has been suggested that its supraphysiological administration may strengthen connective tissue thereby paralleling increase in strength brought about by exercise (or other measures such as anabolic steroids), thus decreasing risk of injury to these tissues. Third, GH has anectodal side effects such as improving skin tone, eyesight and recovery time from injury, all of which may be considered beneficial to the athlete undergoing strenuous training. Fourth, athletes often take performance-enhancing substances in combination, a practice known as stacking. Appropriate, placebo controlled trials using GH in combination with other substances are few. Fifth, at the higher doses reportedly used by athletes, GH may be more effective than at the doses approved for research studies, which are limited due to complications associated with GH administration. The fluid retention which occurs with GH is usually well tolerated and most subjects are happy to remain on GH. Athralgia, carpal tunnel syndrome, oedema and atrial fibrillation are reported in studies using GH administration sometimes leading subjects to withdraw."
So, the author states that in the various studies there is no evidence that GH increases muscle mass in healthy individuals, but that in these studies the dose of GH might be low for muscle mass increase.
"The mechanisms that lead to muscle adaptation to overload are not completely understood. Neither are those that regulate muscle mass development and maintenance. GH and IGF-I clearly play a role in muscle development pre- and postnatally. In GHD adults, there is evidence that serum GH affects muscle mass maintenance, but in healthy adults neither GH nor IGF-I has or enhances the hypertrophic effects of exercise. In contrast, much evidence supports the hypertrophic effect of autocrine/paracrine IGF-I in animals and suggests that it may play a role in adaptation to overload in both animals and humans. Increased muscle expression of IGF-I also enhances the effects of training in animals. Local injection of GH or IGF-I protein or plasmids is effective in animal models and may eventually be used with therapeutic ends. There is evidence for an effect of GH on other performance parameters that is related to increased lean body mass as opposed to increased skeletal muscle mass"
What I found interesting is that they state evidence of local injections of GH or IGF1 being capable of increasing muscle mass locally.
Anyone have an opinion on this?
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Originally Posted by marcus300
