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04-08-2006, 07:49 AM
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Rank: Member
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Join Date: Mar 2006
Posts: 54
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Arginine Alpha-Ketoglutarate (AKG / AAKG):
Quote:
Arginine alpha-ketoglutarate (AKG) is a salt formed by combining two molecules of the amino acid Arginine and one molecule of alpha-ketoglutarate. Because AKG seems to be involved in amino acid synthesis and protein availability, many athletes supplement with AKG as a way to increase muscle mass and strength – although the evidence for its effectiveness is this regard is quite limited.
Increases muscle size and strength
Reduces body fat
Stimulates the immune system
AKG has been used to treat patients suffering from burns, surgery, malnutrition and other trauma. Although the precise mechanism is unknown, AKG treatment decreases muscle protein catabolism (breakdown) and/or increases protein synthesis, in addition to promoting wound healing. AKG may promote the secretion of anabolic hormones such as insulin and growth hormone and increase amino acid metabolism (glutamine & arginine), which may help explain some of the clinical findings.
Scientific Support
Arginine and Arginine are precursors of nitric oxide and polyamines, respectively -metabolites which participate in a number of metabolic functions. AKG supplements have been shown to promote growth hormone and insulin secretion with anabolic effects in postoperative patients. Their intermediary metabolites (glutamine & proline) may also have beneficial effects in promoting recovery from trauma. In animal studies, AKG supplementation increases levels of arginine and glutamine in skeletal muscles and stimulates immune system function compared to animals not receiving AKG. The immunomodulatory properties found with AKG suggest that it may enhance host-defense mechanisms, particularly during injury and acute stress
AKG supplements (15 grams per day for 5 months) have been shown to improve growth rates in small children. The AKG supplements resulted in elevated concentrations of anabolic (growth) hormones and amino acid metabolites, including insulin-like growth factor 1 (IGF1), glutamine and glutamate. In another study of healthy men, AKG given at 10 grams per day resulted in a 20-30% elevation in insulin (another anabolic hormone), which were not observed with supplementation of either Arginine or alpha-ketoglutarate alone.
A test tube study found that AKG induces a significant increase in growth of human fibroblasts – cells with similarities to muscle fiber cells. This effect was dose-dependent, meaning that a more pronounced growth effect was noted with increasing levels of AKG (but not with increasing levels of Arginine or alpha-ketoglutarate alone).
In one study, the anti-catabolic effects of AKG were investigated in 14 multiple trauma patients who were highly catabolic and hyper-metabolic. One group of subjects received 20 grams of AKG per day and showed a significant increase in protein turnover as well as a an increase in blood levels of insulin, growth hormone, and free amino acids (glutamine, proline and Arginine) compared to subjects not receiving AKG supplements.
References:
1. Cochard A, Guilhermet R, Bonneau M. Plasma growth hormone (GH), insulin and amino acid responses to arginine with or without aspartic acid in pigs. Effect of the dose. Reprod Nutr Dev 1998 May-Jun;38(3):331-43.
2. Jeevanandam M, Petersen SR. Substrate fuel kinetics in enterally fed trauma patients supplemented with Arginine alpha ketoglutarate. Clin Nutr 1999 Aug;18(4):209-17.
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