Please Scroll Down to See Forums Below 
interesting article about glutamine ....
There is a strong positive relationship between intracellular glutamine levels and protein synthesis. During muscle-protein wasting associated with injury or disease the levels of free glutamine in muscle tissue falls. In order to find out the consequences of this, MacLennan et al. looked at the relationship between the rate of muscle protein synthesis and intramuscular glutamine concentration (1). These investigators used in-vitro methods in order to acutely view changes in protein synthetic rates. Increasing intramuscular glutamine levels by 200% led to a 66% increase in protein synthesis in the absence of insulin. When they added insulin to the mix, a 30% increase in intramuscular glutamine was accompanied by an 80% increase in protein synthesis. Clearly, increasing the amount of free glutamine inside your muscles increases protein synthesis. Anyone reading this should have one question in mind however, is it possible to increase intramuscular glutamine levels by 200% by using a supplement?…More on that in a minute.
Some in vitro evidence exists that shows glutamine to have a direct effect on protein synthesis, however, this effect may be conditional (2). Zhou and colleagues found that glutamine has a stimulatory effect on the rate of protein synthesis in stressed myotubes but not in normal-cultured myotubes. Myotubes are muscle fibers in their early stages of development. Now, they found that the protective effect of glutamine on skeletal muscle protein might be associated with "heat shock proteins" or HSP. One common HSP in skeletal muscle is HSP70. They found that the level of HSP70 correlated with the levels of glutamine. What does this mean to you? It’s hard to say. It’s too early really at this point to make any conclusive remarks.
If the effect of glutamine on protein synthesis weren’t enough, it appears glutamine may also be anticatabolic. Research has shown that glutamine may exert anticatabolic effects similar to insulin. (3) MacLennan et al. was able to show that, glutamine was just as anti-catabolic as insulin. The anti-catabolic effects of glutamine were not enhanced when combined with insulin, indicating a similar mode of action. This type of anticatabolic effect results in the preservation of soluble or non-contractile proteins with no protective effect on myofibrillar proteins. This would make sense considering glutamines effects on protein breakdown were through a similar mechanism to insulin. This study shows that glutamine is indeed anti-catabolic, but it won’t help you hold on to those muscle proteins that really count.
You may have seen glutamine advertised as a "cell-volumizer". Well, this is true in a way. Glutamine itself doesn’t actually cause cells to swell. It is the sodium that must be co-transported with glutamine that causes the cell to swell. Either way it is a good thing. A consequence of the sodium-dependent entry of glutamine, is an osmotic, or "swelling" of the cell with water. Glutamine has been given a number of anabolic properties such as the stimulation of both protein and glycogen synthesis. The mechanism through which glutamine activates key enzymes in these metabolic pathways may involve this glutamine/sodium-induced cell swelling.(4)
Keep in mind that all of the studies we have looked at have used in-vitro techniques. This is a far cry from in-vivo conditions.
Glutamine may play a role in glycogen repletion after exercise.(5) In a study by Varnier et al. subjects cycled for 90 min at 70-140% VO2max to deplete muscle glycogen; then constant infusions of glutamine or a mixture of alanine and glycine or saline were administered. Muscle glutamine remained constant during saline infusion, decreased 18% during alanine+glycine infusion, but rose 16% during glutamine infusion. By 2 hrs. after exercise, muscle glycogen concentration had increased more in the glutamine-infused group than in the saline or alanine+glycine groups. The rate that blood glucose was incorporated into glycogen was not increased; suggesting that glutamine itself was serving as a substrate for glycogen synthesis rather than increasing glycogen storage from dietary carbs. What this means is that glutamine was being used for gluconeogenesis. This would not be the most practical use of a glutamine supplement. Besides, it would be difficult to mimic the effects of glutamine infusion with an oral glutamine supplement.
So what if you combine glutamine with a glucose polymer? The positive effect of oral glutamine combined with glucose on post exercise glycogen storage was shown to only occur outside of muscle, most likely in the liver.(6) Glutamine does not enhance glycogen synthesis in skeletal muscle beyond what glucose polymers do alone.
The authors of the study combining glutamine with glucose polymers commented that, from their data, only 47-50% of orally administered glutamine can be expected to make it past the liver and other organs, into the blood stream. And only about 10% can be expected to reach extracellular spaces.(6) Now, this is the main argument against glutamine. 90% of the glutamine you take orally never even makes it to your muscles. This isn’t to say it is wasted. Your GI tract loves glutamine from reasons explained earlier. If you are having intestinal problems nothing is better. If you are trying to increase protein synthesis by loading glutamine, it isn’t going to work.
So, is glutamine a "must have" supplement for any aspiring bodybuilder? No, probably not. Is it helpful under situations where overtraining is rearing its ugly head? You bet. Everything considered, glutamine is one of those supplements that probably will benefit anybody preparing for a show, but if you are an off-season, well-fed bodybuilder getting plenty of recovery and using a whey protein supplement, there are more important supplements to spend your money on.
There is a strong positive relationship between intracellular glutamine levels and protein synthesis. During muscle-protein wasting associated with injury or disease the levels of free glutamine in muscle tissue falls. In order to find out the consequences of this, MacLennan et al. looked at the relationship between the rate of muscle protein synthesis and intramuscular glutamine concentration (1). These investigators used in-vitro methods in order to acutely view changes in protein synthetic rates. Increasing intramuscular glutamine levels by 200% led to a 66% increase in protein synthesis in the absence of insulin. When they added insulin to the mix, a 30% increase in intramuscular glutamine was accompanied by an 80% increase in protein synthesis. Clearly, increasing the amount of free glutamine inside your muscles increases protein synthesis. Anyone reading this should have one question in mind however, is it possible to increase intramuscular glutamine levels by 200% by using a supplement?…More on that in a minute.
Some in vitro evidence exists that shows glutamine to have a direct effect on protein synthesis, however, this effect may be conditional (2). Zhou and colleagues found that glutamine has a stimulatory effect on the rate of protein synthesis in stressed myotubes but not in normal-cultured myotubes. Myotubes are muscle fibers in their early stages of development. Now, they found that the protective effect of glutamine on skeletal muscle protein might be associated with "heat shock proteins" or HSP. One common HSP in skeletal muscle is HSP70. They found that the level of HSP70 correlated with the levels of glutamine. What does this mean to you? It’s hard to say. It’s too early really at this point to make any conclusive remarks.
If the effect of glutamine on protein synthesis weren’t enough, it appears glutamine may also be anticatabolic. Research has shown that glutamine may exert anticatabolic effects similar to insulin. (3) MacLennan et al. was able to show that, glutamine was just as anti-catabolic as insulin. The anti-catabolic effects of glutamine were not enhanced when combined with insulin, indicating a similar mode of action. This type of anticatabolic effect results in the preservation of soluble or non-contractile proteins with no protective effect on myofibrillar proteins. This would make sense considering glutamines effects on protein breakdown were through a similar mechanism to insulin. This study shows that glutamine is indeed anti-catabolic, but it won’t help you hold on to those muscle proteins that really count.
You may have seen glutamine advertised as a "cell-volumizer". Well, this is true in a way. Glutamine itself doesn’t actually cause cells to swell. It is the sodium that must be co-transported with glutamine that causes the cell to swell. Either way it is a good thing. A consequence of the sodium-dependent entry of glutamine, is an osmotic, or "swelling" of the cell with water. Glutamine has been given a number of anabolic properties such as the stimulation of both protein and glycogen synthesis. The mechanism through which glutamine activates key enzymes in these metabolic pathways may involve this glutamine/sodium-induced cell swelling.(4)
Keep in mind that all of the studies we have looked at have used in-vitro techniques. This is a far cry from in-vivo conditions.
Glutamine may play a role in glycogen repletion after exercise.(5) In a study by Varnier et al. subjects cycled for 90 min at 70-140% VO2max to deplete muscle glycogen; then constant infusions of glutamine or a mixture of alanine and glycine or saline were administered. Muscle glutamine remained constant during saline infusion, decreased 18% during alanine+glycine infusion, but rose 16% during glutamine infusion. By 2 hrs. after exercise, muscle glycogen concentration had increased more in the glutamine-infused group than in the saline or alanine+glycine groups. The rate that blood glucose was incorporated into glycogen was not increased; suggesting that glutamine itself was serving as a substrate for glycogen synthesis rather than increasing glycogen storage from dietary carbs. What this means is that glutamine was being used for gluconeogenesis. This would not be the most practical use of a glutamine supplement. Besides, it would be difficult to mimic the effects of glutamine infusion with an oral glutamine supplement.
So what if you combine glutamine with a glucose polymer? The positive effect of oral glutamine combined with glucose on post exercise glycogen storage was shown to only occur outside of muscle, most likely in the liver.(6) Glutamine does not enhance glycogen synthesis in skeletal muscle beyond what glucose polymers do alone.
The authors of the study combining glutamine with glucose polymers commented that, from their data, only 47-50% of orally administered glutamine can be expected to make it past the liver and other organs, into the blood stream. And only about 10% can be expected to reach extracellular spaces.(6) Now, this is the main argument against glutamine. 90% of the glutamine you take orally never even makes it to your muscles. This isn’t to say it is wasted. Your GI tract loves glutamine from reasons explained earlier. If you are having intestinal problems nothing is better. If you are trying to increase protein synthesis by loading glutamine, it isn’t going to work.
So, is glutamine a "must have" supplement for any aspiring bodybuilder? No, probably not. Is it helpful under situations where overtraining is rearing its ugly head? You bet. Everything considered, glutamine is one of those supplements that probably will benefit anybody preparing for a show, but if you are an off-season, well-fed bodybuilder getting plenty of recovery and using a whey protein supplement, there are more important supplements to spend your money on.
